chore: replace int amount_cents for string storage and decimal pkg

internal/db/migrations/00018_add_decimal_amount_columns.sql

@@ -0,0 +1,54 @@
+-- +goose Up
+
+-- expenses
+ALTER TABLE expenses ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE expenses SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- account_transfers
+ALTER TABLE account_transfers ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE account_transfers SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- recurring_expenses
+ALTER TABLE recurring_expenses ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE recurring_expenses SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- budgets
+ALTER TABLE budgets ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE budgets SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- recurring_deposits
+ALTER TABLE recurring_deposits ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE recurring_deposits SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- loans
+ALTER TABLE loans ADD COLUMN original_amount TEXT NOT NULL DEFAULT '0';
+UPDATE loans SET original_amount = CAST(original_amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(original_amount_cents) % 100 AS TEXT), -2, 2);
+
+-- recurring_receipts
+ALTER TABLE recurring_receipts ADD COLUMN total_amount TEXT NOT NULL DEFAULT '0';
+UPDATE recurring_receipts SET total_amount = CAST(total_amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(total_amount_cents) % 100 AS TEXT), -2, 2);
+
+-- recurring_receipt_sources
+ALTER TABLE recurring_receipt_sources ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE recurring_receipt_sources SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- receipts
+ALTER TABLE receipts ADD COLUMN total_amount TEXT NOT NULL DEFAULT '0';
+UPDATE receipts SET total_amount = CAST(total_amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(total_amount_cents) % 100 AS TEXT), -2, 2);
+
+-- receipt_funding_sources
+ALTER TABLE receipt_funding_sources ADD COLUMN amount TEXT NOT NULL DEFAULT '0';
+UPDATE receipt_funding_sources SET amount = CAST(amount_cents / 100 AS TEXT) || '.' || SUBSTR('00' || CAST(ABS(amount_cents) % 100 AS TEXT), -2, 2);
+
+-- +goose Down
+-- SQLite does not support DROP COLUMN in older versions, but modernc.org/sqlite supports it.
+ALTER TABLE expenses DROP COLUMN amount;
+ALTER TABLE account_transfers DROP COLUMN amount;
+ALTER TABLE recurring_expenses DROP COLUMN amount;
+ALTER TABLE budgets DROP COLUMN amount;
+ALTER TABLE recurring_deposits DROP COLUMN amount;
+ALTER TABLE loans DROP COLUMN original_amount;
+ALTER TABLE recurring_receipts DROP COLUMN total_amount;
+ALTER TABLE recurring_receipt_sources DROP COLUMN amount;
+ALTER TABLE receipts DROP COLUMN total_amount;
+ALTER TABLE receipt_funding_sources DROP COLUMN amount;

internal/handler/space.go

@@ -156,9 +156,9 @@ func (h *SpaceHandler) OverviewPage(w http.ResponseWriter, r *http.Request) {
 	allocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		allocated = 0
+		allocated = decimal.Zero
 	}
-	balance -= allocated
+	balance = balance.Sub(allocated)
 
 	// This month's report
 	now := time.Now()
@@ -578,9 +578,9 @@ func (h *SpaceHandler) ExpensesPage(w http.ResponseWriter, r *http.Request) {
 	totalAllocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		totalAllocated = 0
+		totalAllocated = decimal.Zero
 	}
-	balance -= totalAllocated
+	balance = balance.Sub(totalAllocated)
 
 	tags, err := h.tagService.GetTagsForSpace(spaceID)
 	if err != nil {
@@ -639,12 +639,11 @@ func (h *SpaceHandler) CreateExpense(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount format.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	date, err := time.Parse("2006-01-02", dateStr)
 	if err != nil {
@@ -717,7 +716,7 @@ func (h *SpaceHandler) CreateExpense(w http.ResponseWriter, r *http.Request) {
 		SpaceID:         spaceID,
 		UserID:          user.ID,
 		Description:     description,
-		Amount:          amountCents,
+		Amount:          amount,
 		Type:            expenseType,
 		Date:            date,
 		TagIDs:          finalTagIDs,
@@ -760,9 +759,9 @@ func (h *SpaceHandler) CreateExpense(w http.ResponseWriter, r *http.Request) {
 	totalAllocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		totalAllocated = 0
+		totalAllocated = decimal.Zero
 	}
-	balance -= totalAllocated
+	balance = balance.Sub(totalAllocated)
 
 	// Return the full paginated list for page 1 so the new expense appears
 	expenses, totalPages, err := h.expenseService.GetExpensesWithTagsAndMethodsForSpacePaginated(spaceID, 1)
@@ -809,12 +808,11 @@ func (h *SpaceHandler) UpdateExpense(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount format.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	date, err := time.Parse("2006-01-02", dateStr)
 	if err != nil {
@@ -874,7 +872,7 @@ func (h *SpaceHandler) UpdateExpense(w http.ResponseWriter, r *http.Request) {
 		ID:              expenseID,
 		SpaceID:         spaceID,
 		Description:     description,
-		Amount:          amountCents,
+		Amount:          amount,
 		Type:            expenseType,
 		Date:            date,
 		TagIDs:          finalTagIDs,
@@ -904,9 +902,9 @@ func (h *SpaceHandler) UpdateExpense(w http.ResponseWriter, r *http.Request) {
 	totalAllocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		totalAllocated = 0
+		totalAllocated = decimal.Zero
 	}
-	balance -= totalAllocated
+	balance = balance.Sub(totalAllocated)
 
 	methods, _ := h.methodService.GetMethodsForSpace(spaceID)
 	updatedTags, _ := h.tagService.GetTagsForSpace(spaceID)
@@ -935,9 +933,9 @@ func (h *SpaceHandler) DeleteExpense(w http.ResponseWriter, r *http.Request) {
 	totalAllocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		totalAllocated = 0
+		totalAllocated = decimal.Zero
 	}
-	balance -= totalAllocated
+	balance = balance.Sub(totalAllocated)
 
 	ui.Render(w, r, expense.BalanceCard(spaceID, balance, totalAllocated, true))
 	ui.RenderToast(w, r, toast.Toast(toast.Props{
@@ -1033,9 +1031,9 @@ func (h *SpaceHandler) GetBalanceCard(w http.ResponseWriter, r *http.Request) {
 	totalAllocated, err := h.accountService.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
-		totalAllocated = 0
+		totalAllocated = decimal.Zero
 	}
-	balance -= totalAllocated
+	balance = balance.Sub(totalAllocated)
 
 	ui.Render(w, r, expense.BalanceCard(spaceID, balance, totalAllocated, false))
 }
@@ -1361,7 +1359,7 @@ func (h *SpaceHandler) AccountsPage(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	availableBalance := totalBalance - totalAllocated
+	availableBalance := totalBalance.Sub(totalAllocated)
 
 	transfers, totalPages, err := h.accountService.GetTransfersForSpacePaginated(spaceID, 1)
 	if err != nil {
@@ -1401,7 +1399,7 @@ func (h *SpaceHandler) CreateAccount(w http.ResponseWriter, r *http.Request) {
 
 	acctWithBalance := model.MoneyAccountWithBalance{
 		MoneyAccount: *account,
-		BalanceCents: 0,
+		Balance:      decimal.Zero,
 	}
 
 	ui.Render(w, r, moneyaccount.AccountCard(spaceID, &acctWithBalance))
@@ -1445,7 +1443,7 @@ func (h *SpaceHandler) UpdateAccount(w http.ResponseWriter, r *http.Request) {
 
 	acctWithBalance := model.MoneyAccountWithBalance{
 		MoneyAccount: *updatedAccount,
-		BalanceCents: balance,
+		Balance:      balance,
 	}
 
 	ui.Render(w, r, moneyaccount.AccountCard(spaceID, &acctWithBalance))
@@ -1476,7 +1474,7 @@ func (h *SpaceHandler) DeleteAccount(w http.ResponseWriter, r *http.Request) {
 		slog.Error("failed to get total allocated", "error", err, "space_id", spaceID)
 	}
 
-	ui.Render(w, r, moneyaccount.BalanceSummaryCard(spaceID, totalBalance, totalBalance-totalAllocated, true))
+	ui.Render(w, r, moneyaccount.BalanceSummaryCard(spaceID, totalBalance, totalBalance.Sub(totalAllocated), true))
 	ui.RenderToast(w, r, toast.Toast(toast.Props{
 		Title:       "Account deleted",
 		Variant:     toast.VariantSuccess,
@@ -1504,12 +1502,11 @@ func (h *SpaceHandler) CreateTransfer(w http.ResponseWriter, r *http.Request) {
 	direction := model.TransferDirection(r.FormValue("direction"))
 	note := r.FormValue("note")
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
-	if err != nil || amountDecimal.LessThanOrEqual(decimal.Zero) {
+	amount, err := decimal.NewFromString(amountStr)
+	if err != nil || amount.LessThanOrEqual(decimal.Zero) {
 		ui.RenderError(w, r, "Invalid amount", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	// Calculate available space balance for deposit validation
 	totalBalance, err := h.expenseService.GetBalanceForSpace(spaceID)
@@ -1524,11 +1521,11 @@ func (h *SpaceHandler) CreateTransfer(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 		return
 	}
-	availableBalance := totalBalance - totalAllocated
+	availableBalance := totalBalance.Sub(totalAllocated)
 
 	// Validate balance limits before creating transfer
-	if direction == model.TransferDirectionDeposit && amountCents > availableBalance {
-		ui.RenderError(w, r, fmt.Sprintf("Insufficient available balance. You can deposit up to $%.2f.", float64(availableBalance)/100.0), http.StatusUnprocessableEntity)
+	if direction == model.TransferDirectionDeposit && amount.GreaterThan(availableBalance) {
+		ui.RenderError(w, r, fmt.Sprintf("Insufficient available balance. You can deposit up to %s.", model.FormatMoney(availableBalance)), http.StatusUnprocessableEntity)
 		return
 	}
 
@@ -1539,15 +1536,15 @@ func (h *SpaceHandler) CreateTransfer(w http.ResponseWriter, r *http.Request) {
 			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 			return
 		}
-		if amountCents > acctBalance {
-			ui.RenderError(w, r, fmt.Sprintf("Insufficient account balance. You can withdraw up to $%.2f.", float64(acctBalance)/100.0), http.StatusUnprocessableEntity)
+		if amount.GreaterThan(acctBalance) {
+			ui.RenderError(w, r, fmt.Sprintf("Insufficient account balance. You can withdraw up to %s.", model.FormatMoney(acctBalance)), http.StatusUnprocessableEntity)
 			return
 		}
 	}
 
 	_, err = h.accountService.CreateTransfer(service.CreateTransferDTO{
 		AccountID: accountID,
-		Amount:    amountCents,
+		Amount:    amount,
 		Direction: direction,
 		Note:      note,
 		CreatedBy: user.ID,
@@ -1569,12 +1566,12 @@ func (h *SpaceHandler) CreateTransfer(w http.ResponseWriter, r *http.Request) {
 	account, _ := h.accountService.GetAccount(accountID)
 	acctWithBalance := model.MoneyAccountWithBalance{
 		MoneyAccount: *account,
-		BalanceCents: accountBalance,
+		Balance:      accountBalance,
 	}
 
 	// Recalculate available balance after transfer
 	totalAllocated, _ = h.accountService.GetTotalAllocatedForSpace(spaceID)
-	newAvailable := totalBalance - totalAllocated
+	newAvailable := totalBalance.Sub(totalAllocated)
 
 	w.Header().Set("HX-Trigger", "transferSuccess")
 	ui.Render(w, r, moneyaccount.AccountCard(spaceID, &acctWithBalance, true))
@@ -1611,14 +1608,14 @@ func (h *SpaceHandler) DeleteTransfer(w http.ResponseWriter, r *http.Request) {
 	account, _ := h.accountService.GetAccount(accountID)
 	acctWithBalance := model.MoneyAccountWithBalance{
 		MoneyAccount: *account,
-		BalanceCents: accountBalance,
+		Balance:      accountBalance,
 	}
 
 	totalBalance, _ := h.expenseService.GetBalanceForSpace(spaceID)
 	totalAllocated, _ := h.accountService.GetTotalAllocatedForSpace(spaceID)
 
 	ui.Render(w, r, moneyaccount.AccountCard(spaceID, &acctWithBalance, true))
-	ui.Render(w, r, moneyaccount.BalanceSummaryCard(spaceID, totalBalance, totalBalance-totalAllocated, true))
+	ui.Render(w, r, moneyaccount.BalanceSummaryCard(spaceID, totalBalance, totalBalance.Sub(totalAllocated), true))
 
 	transfers, transferTotalPages, _ := h.accountService.GetTransfersForSpacePaginated(spaceID, 1)
 	ui.Render(w, r, moneyaccount.TransferHistoryContent(spaceID, transfers, 1, transferTotalPages, true))
@@ -1693,12 +1690,11 @@ func (h *SpaceHandler) CreateRecurringDeposit(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
-	if err != nil || amountDecimal.LessThanOrEqual(decimal.Zero) {
+	amount, err := decimal.NewFromString(amountStr)
+	if err != nil || amount.LessThanOrEqual(decimal.Zero) {
 		ui.RenderError(w, r, "Invalid amount.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -1719,7 +1715,7 @@ func (h *SpaceHandler) CreateRecurringDeposit(w http.ResponseWriter, r *http.Req
 	rd, err := h.recurringDepositService.CreateRecurringDeposit(service.CreateRecurringDepositDTO{
 		SpaceID:   spaceID,
 		AccountID: accountID,
-		Amount:    amountCents,
+		Amount:    amount,
 		Frequency: model.Frequency(frequencyStr),
 		StartDate: startDate,
 		EndDate:   endDate,
@@ -1780,12 +1776,11 @@ func (h *SpaceHandler) UpdateRecurringDeposit(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
-	if err != nil || amountDecimal.LessThanOrEqual(decimal.Zero) {
+	amount, err := decimal.NewFromString(amountStr)
+	if err != nil || amount.LessThanOrEqual(decimal.Zero) {
 		ui.RenderError(w, r, "Invalid amount.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -1806,7 +1801,7 @@ func (h *SpaceHandler) UpdateRecurringDeposit(w http.ResponseWriter, r *http.Req
 	updated, err := h.recurringDepositService.UpdateRecurringDeposit(service.UpdateRecurringDepositDTO{
 		ID:        recurringDepositID,
 		AccountID: accountID,
-		Amount:    amountCents,
+		Amount:    amount,
 		Frequency: model.Frequency(frequencyStr),
 		StartDate: startDate,
 		EndDate:   endDate,
@@ -2082,12 +2077,11 @@ func (h *SpaceHandler) CreateRecurringExpense(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount format.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -2156,7 +2150,7 @@ func (h *SpaceHandler) CreateRecurringExpense(w http.ResponseWriter, r *http.Req
 		SpaceID:         spaceID,
 		UserID:          user.ID,
 		Description:     description,
-		Amount:          amountCents,
+		Amount:          amount,
 		Type:            expenseType,
 		PaymentMethodID: paymentMethodID,
 		Frequency:       frequency,
@@ -2210,12 +2204,11 @@ func (h *SpaceHandler) UpdateRecurringExpense(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -2270,7 +2263,7 @@ func (h *SpaceHandler) UpdateRecurringExpense(w http.ResponseWriter, r *http.Req
 	updated, err := h.recurringService.UpdateRecurringExpense(service.UpdateRecurringExpenseDTO{
 		ID:              recurringID,
 		Description:     description,
-		Amount:          amountCents,
+		Amount:          amount,
 		Type:            model.ExpenseType(typeStr),
 		PaymentMethodID: paymentMethodID,
 		Frequency:       model.Frequency(frequencyStr),
@@ -2464,12 +2457,11 @@ func (h *SpaceHandler) CreateBudget(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -2490,7 +2482,7 @@ func (h *SpaceHandler) CreateBudget(w http.ResponseWriter, r *http.Request) {
 	_, err = h.budgetService.CreateBudget(service.CreateBudgetDTO{
 		SpaceID:   spaceID,
 		TagIDs:    tagIDs,
-		Amount:    amountCents,
+		Amount:    amount,
 		Period:    model.BudgetPeriod(periodStr),
 		StartDate: startDate,
 		EndDate:   endDate,
@@ -2544,12 +2536,11 @@ func (h *SpaceHandler) UpdateBudget(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	amountDecimal, err := decimal.NewFromString(amountStr)
+	amount, err := decimal.NewFromString(amountStr)
 	if err != nil {
 		ui.RenderError(w, r, "Invalid amount.", http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amountDecimal.Mul(decimal.NewFromInt(100)).IntPart())
 
 	startDate, err := time.Parse("2006-01-02", startDateStr)
 	if err != nil {
@@ -2570,7 +2561,7 @@ func (h *SpaceHandler) UpdateBudget(w http.ResponseWriter, r *http.Request) {
 	_, err = h.budgetService.UpdateBudget(service.UpdateBudgetDTO{
 		ID:        budgetID,
 		TagIDs:    tagIDs,
-		Amount:    amountCents,
+		Amount:    amount,
 		Period:    model.BudgetPeriod(periodStr),
 		StartDate: startDate,
 		EndDate:   endDate,

internal/handler/space_loans.go

@@ -62,8 +62,6 @@ func (h *SpaceHandler) CreateLoan(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	interestStr := r.FormValue("interest_rate")
 	var interestBps int
 	if interestStr != "" {
@@ -93,7 +91,7 @@ func (h *SpaceHandler) CreateLoan(w http.ResponseWriter, r *http.Request) {
 		UserID:          user.ID,
 		Name:            name,
 		Description:     description,
-		OriginalAmount:  amountCents,
+		OriginalAmount:  amount,
 		InterestRateBps: interestBps,
 		StartDate:       startDate,
 		EndDate:         endDate,
@@ -165,7 +163,7 @@ func (h *SpaceHandler) LoanDetailPage(w http.ResponseWriter, r *http.Request) {
 	balance, err := h.expenseService.GetBalanceForSpace(spaceID)
 	if err != nil {
 		slog.Error("failed to get balance", "error", err)
-		balance = 0
+		balance = decimal.Zero
 	}
 
 	ui.Render(w, r, pages.SpaceLoanDetailPage(space, loan, receipts, page, totalPages, recurringReceipts, accounts, balance))
@@ -190,8 +188,6 @@ func (h *SpaceHandler) UpdateLoan(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	amountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	interestStr := r.FormValue("interest_rate")
 	var interestBps int
 	if interestStr != "" {
@@ -220,7 +216,7 @@ func (h *SpaceHandler) UpdateLoan(w http.ResponseWriter, r *http.Request) {
 		ID:              loanID,
 		Name:            name,
 		Description:     description,
-		OriginalAmount:  amountCents,
+		OriginalAmount:  amount,
 		InterestRateBps: interestBps,
 		StartDate:       startDate,
 		EndDate:         endDate,
@@ -267,8 +263,6 @@ func (h *SpaceHandler) CreateReceipt(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	totalAmountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	dateStr := r.FormValue("date")
 	date, err := time.Parse("2006-01-02", dateStr)
 	if err != nil {
@@ -288,7 +282,7 @@ func (h *SpaceHandler) CreateReceipt(w http.ResponseWriter, r *http.Request) {
 		SpaceID:        spaceID,
 		UserID:         user.ID,
 		Description:    description,
-		TotalAmount:    totalAmountCents,
+		TotalAmount:    amount,
 		Date:           date,
 		FundingSources: fundingSources,
 	}
@@ -320,8 +314,6 @@ func (h *SpaceHandler) UpdateReceipt(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	totalAmountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	dateStr := r.FormValue("date")
 	date, err := time.Parse("2006-01-02", dateStr)
 	if err != nil {
@@ -340,7 +332,7 @@ func (h *SpaceHandler) UpdateReceipt(w http.ResponseWriter, r *http.Request) {
 		SpaceID:        spaceID,
 		UserID:         user.ID,
 		Description:    description,
-		TotalAmount:    totalAmountCents,
+		TotalAmount:    amount,
 		Date:           date,
 		FundingSources: fundingSources,
 	}
@@ -405,8 +397,6 @@ func (h *SpaceHandler) CreateRecurringReceipt(w http.ResponseWriter, r *http.Req
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	totalAmountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	frequency := model.Frequency(r.FormValue("frequency"))
 
 	startDateStr := r.FormValue("start_date")
@@ -436,7 +426,7 @@ func (h *SpaceHandler) CreateRecurringReceipt(w http.ResponseWriter, r *http.Req
 		SpaceID:        spaceID,
 		UserID:         user.ID,
 		Description:    description,
-		TotalAmount:    totalAmountCents,
+		TotalAmount:    amount,
 		Frequency:      frequency,
 		StartDate:      startDate,
 		EndDate:        endDate,
@@ -468,8 +458,6 @@ func (h *SpaceHandler) UpdateRecurringReceipt(w http.ResponseWriter, r *http.Req
 		w.WriteHeader(http.StatusUnprocessableEntity)
 		return
 	}
-	totalAmountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 	frequency := model.Frequency(r.FormValue("frequency"))
 
 	startDateStr := r.FormValue("start_date")
@@ -497,7 +485,7 @@ func (h *SpaceHandler) UpdateRecurringReceipt(w http.ResponseWriter, r *http.Req
 	dto := service.UpdateRecurringReceiptDTO{
 		ID:             recurringReceiptID,
 		Description:    description,
-		TotalAmount:    totalAmountCents,
+		TotalAmount:    amount,
 		Frequency:      frequency,
 		StartDate:      startDate,
 		EndDate:        endDate,
@@ -570,11 +558,9 @@ func parseFundingSources(r *http.Request) ([]service.FundingSourceDTO, error) {
 		if err != nil || amount.LessThanOrEqual(decimal.Zero) {
 			return nil, fmt.Errorf("invalid funding source amount")
 		}
-		amountCents := int(amount.Mul(decimal.NewFromInt(100)).IntPart())
-
 		src := service.FundingSourceDTO{
 			SourceType: model.FundingSourceType(srcType),
-			Amount:     amountCents,
+			Amount:     amount,
 		}
 
 		if srcType == string(model.FundingSourceAccount) {

internal/model/budget.go

@@ -3,6 +3,8 @@ package model
 import (
 	"strings"
 	"time"
+
+	"github.com/shopspring/decimal"
 )
 
 type BudgetPeriod string
@@ -24,7 +26,8 @@ const (
 type Budget struct {
 	ID          string          `db:"id"`
 	SpaceID     string          `db:"space_id"`
-	AmountCents int          `db:"amount_cents"`
+	Amount      decimal.Decimal `db:"amount"`
+	AmountCents int             `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	Period      BudgetPeriod    `db:"period"`
 	StartDate   time.Time       `db:"start_date"`
 	EndDate     *time.Time      `db:"end_date"`
@@ -37,7 +40,7 @@ type Budget struct {
 type BudgetWithSpent struct {
 	Budget
 	Tags       []*Tag
-	SpentCents int
+	Spent      decimal.Decimal
 	Percentage float64
 	Status     BudgetStatus
 }

internal/model/expense.go

@@ -1,6 +1,10 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type ExpenseType string
 
@@ -14,7 +18,8 @@ type Expense struct {
 	SpaceID            string          `db:"space_id"`
 	CreatedBy          string          `db:"created_by"`
 	Description        string          `db:"description"`
-	AmountCents        int         `db:"amount_cents"`
+	Amount             decimal.Decimal `db:"amount"`
+	AmountCents        int             `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	Type               ExpenseType     `db:"type"`
 	Date               time.Time       `db:"date"`
 	PaymentMethodID    *string         `db:"payment_method_id"`
@@ -48,5 +53,5 @@ type TagExpenseSummary struct {
 	TagID       string          `db:"tag_id"`
 	TagName     string          `db:"tag_name"`
 	TagColor    *string         `db:"tag_color"`
-	TotalAmount int     `db:"total_amount"`
+	TotalAmount decimal.Decimal `db:"total_amount"`
 }

internal/model/loan.go

@@ -1,13 +1,18 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type Loan struct {
 	ID                  string          `db:"id"`
 	SpaceID             string          `db:"space_id"`
 	Name                string          `db:"name"`
 	Description         string          `db:"description"`
-	OriginalAmountCents int        `db:"original_amount_cents"`
+	OriginalAmount      decimal.Decimal `db:"original_amount"`
+	OriginalAmountCents int             `db:"original_amount_cents"` // deprecated: kept for SELECT * compatibility
 	InterestRateBps     int             `db:"interest_rate_bps"`
 	StartDate           time.Time       `db:"start_date"`
 	EndDate             *time.Time      `db:"end_date"`
@@ -19,7 +24,7 @@ type Loan struct {
 
 type LoanWithPaymentSummary struct {
 	Loan
-	TotalPaidCents int
-	RemainingCents int
+	TotalPaid    decimal.Decimal
+	Remaining    decimal.Decimal
 	ReceiptCount int
 }

internal/model/money.go

@@ -0,0 +1,17 @@
+package model
+
+import (
+	"fmt"
+
+	"github.com/shopspring/decimal"
+)
+
+// FormatMoney formats a decimal as a dollar string like "$12.50"
+func FormatMoney(d decimal.Decimal) string {
+	return fmt.Sprintf("$%s", d.StringFixed(2))
+}
+
+// FormatDecimal formats a decimal for form input values like "12.50"
+func FormatDecimal(d decimal.Decimal) string {
+	return d.StringFixed(2)
+}

internal/model/money_account.go

@@ -1,6 +1,10 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type TransferDirection string
 
@@ -21,7 +25,8 @@ type MoneyAccount struct {
 type AccountTransfer struct {
 	ID                 string            `db:"id"`
 	AccountID          string            `db:"account_id"`
-	AmountCents        int               `db:"amount_cents"`
+	Amount             decimal.Decimal   `db:"amount"`
+	AmountCents        int               `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	Direction          TransferDirection `db:"direction"`
 	Note               string            `db:"note"`
 	RecurringDepositID *string           `db:"recurring_deposit_id"`
@@ -31,7 +36,7 @@ type AccountTransfer struct {
 
 type MoneyAccountWithBalance struct {
 	MoneyAccount
-	BalanceCents int
+	Balance decimal.Decimal
 }
 
 type AccountTransferWithAccount struct {

internal/model/receipt.go

@@ -1,6 +1,10 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type FundingSourceType string
 
@@ -14,7 +18,8 @@ type Receipt struct {
 	LoanID             string          `db:"loan_id"`
 	SpaceID            string          `db:"space_id"`
 	Description        string          `db:"description"`
-	TotalAmountCents   int       `db:"total_amount_cents"`
+	TotalAmount        decimal.Decimal `db:"total_amount"`
+	TotalAmountCents   int             `db:"total_amount_cents"` // deprecated: kept for SELECT * compatibility
 	Date               time.Time       `db:"date"`
 	RecurringReceiptID *string         `db:"recurring_receipt_id"`
 	CreatedBy          string          `db:"created_by"`
@@ -27,7 +32,8 @@ type ReceiptFundingSource struct {
 	ReceiptID        string            `db:"receipt_id"`
 	SourceType       FundingSourceType `db:"source_type"`
 	AccountID        *string           `db:"account_id"`
-	AmountCents      int               `db:"amount_cents"`
+	Amount           decimal.Decimal   `db:"amount"`
+	AmountCents      int               `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	LinkedExpenseID  *string           `db:"linked_expense_id"`
 	LinkedTransferID *string           `db:"linked_transfer_id"`
 }

internal/model/recurring_deposit.go

@@ -1,12 +1,17 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type RecurringDeposit struct {
 	ID             string          `db:"id"`
 	SpaceID        string          `db:"space_id"`
 	AccountID      string          `db:"account_id"`
-	AmountCents    int        `db:"amount_cents"`
+	Amount         decimal.Decimal `db:"amount"`
+	AmountCents    int             `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	Frequency      Frequency       `db:"frequency"`
 	StartDate      time.Time       `db:"start_date"`
 	EndDate        *time.Time      `db:"end_date"`

internal/model/recurring_expense.go

@@ -1,6 +1,10 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type Frequency string
 
@@ -17,7 +21,8 @@ type RecurringExpense struct {
 	SpaceID         string          `db:"space_id"`
 	CreatedBy       string          `db:"created_by"`
 	Description     string          `db:"description"`
-	AmountCents     int         `db:"amount_cents"`
+	Amount          decimal.Decimal `db:"amount"`
+	AmountCents     int             `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 	Type            ExpenseType     `db:"type"`
 	PaymentMethodID *string         `db:"payment_method_id"`
 	Frequency       Frequency       `db:"frequency"`

internal/model/recurring_receipt.go

@@ -1,13 +1,18 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type RecurringReceipt struct {
 	ID               string          `db:"id"`
 	LoanID           string          `db:"loan_id"`
 	SpaceID          string          `db:"space_id"`
 	Description      string          `db:"description"`
-	TotalAmountCents int        `db:"total_amount_cents"`
+	TotalAmount      decimal.Decimal `db:"total_amount"`
+	TotalAmountCents int             `db:"total_amount_cents"` // deprecated: kept for SELECT * compatibility
 	Frequency        Frequency       `db:"frequency"`
 	StartDate        time.Time       `db:"start_date"`
 	EndDate          *time.Time      `db:"end_date"`
@@ -23,7 +28,8 @@ type RecurringReceiptSource struct {
 	RecurringReceiptID string            `db:"recurring_receipt_id"`
 	SourceType         FundingSourceType `db:"source_type"`
 	AccountID          *string           `db:"account_id"`
-	AmountCents        int               `db:"amount_cents"`
+	Amount             decimal.Decimal   `db:"amount"`
+	AmountCents        int               `db:"amount_cents"` // deprecated: kept for SELECT * compatibility
 }
 
 type RecurringReceiptWithSources struct {

internal/model/report.go

@@ -1,15 +1,19 @@
 package model
 
-import "time"
+import (
+	"time"
+
+	"github.com/shopspring/decimal"
+)
 
 type DailySpending struct {
 	Date  time.Time       `db:"date"`
-	TotalCents int       `db:"total_cents"`
+	Total decimal.Decimal `db:"total"`
 }
 
 type MonthlySpending struct {
 	Month string          `db:"month"`
-	TotalCents int    `db:"total_cents"`
+	Total decimal.Decimal `db:"total"`
 }
 
 type SpendingReport struct {
@@ -17,7 +21,7 @@ type SpendingReport struct {
 	DailySpending   []*DailySpending
 	MonthlySpending []*MonthlySpending
 	TopExpenses     []*ExpenseWithTagsAndMethod
-	TotalIncome     int
-	TotalExpenses   int
-	NetBalance      int
+	TotalIncome     decimal.Decimal
+	TotalExpenses   decimal.Decimal
+	NetBalance      decimal.Decimal
 }

internal/repository/budget.go

@@ -7,6 +7,7 @@ import (
 
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 var (
@@ -17,7 +18,7 @@ type BudgetRepository interface {
 	Create(budget *model.Budget, tagIDs []string) error
 	GetByID(id string) (*model.Budget, error)
 	GetBySpaceID(spaceID string) ([]*model.Budget, error)
-	GetSpentForBudget(spaceID string, tagIDs []string, periodStart, periodEnd time.Time) (int, error)
+	GetSpentForBudget(spaceID string, tagIDs []string, periodStart, periodEnd time.Time) (decimal.Decimal, error)
 	GetTagsByBudgetIDs(budgetIDs []string) (map[string][]*model.Tag, error)
 	Update(budget *model.Budget, tagIDs []string) error
 	Delete(id string) error
@@ -38,9 +39,9 @@ func (r *budgetRepository) Create(budget *model.Budget, tagIDs []string) error {
 	}
 	defer tx.Rollback()
 
-	query := `INSERT INTO budgets (id, space_id, amount_cents, period, start_date, end_date, is_active, created_by, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10);`
-	_, err = tx.Exec(query, budget.ID, budget.SpaceID, budget.AmountCents, budget.Period, budget.StartDate, budget.EndDate, budget.IsActive, budget.CreatedBy, budget.CreatedAt, budget.UpdatedAt)
+	query := `INSERT INTO budgets (id, space_id, amount, period, start_date, end_date, is_active, created_by, created_at, updated_at, amount_cents)
+		Values ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, 0);`
+	_, err = tx.Exec(query, budget.ID, budget.SpaceID, budget.Amount, budget.Period, budget.StartDate, budget.EndDate, budget.IsActive, budget.CreatedBy, budget.CreatedAt, budget.UpdatedAt)
 	if err != nil {
 		return err
 	}
@@ -72,23 +73,23 @@ func (r *budgetRepository) GetBySpaceID(spaceID string) ([]*model.Budget, error)
 	return budgets, err
 }
 
-func (r *budgetRepository) GetSpentForBudget(spaceID string, tagIDs []string, periodStart, periodEnd time.Time) (int, error) {
+func (r *budgetRepository) GetSpentForBudget(spaceID string, tagIDs []string, periodStart, periodEnd time.Time) (decimal.Decimal, error) {
 	if len(tagIDs) == 0 {
-		return 0, nil
+		return decimal.Zero, nil
 	}
 
 	query, args, err := sqlx.In(`
-		SELECT COALESCE(SUM(e.amount_cents), 0)
+		SELECT COALESCE(SUM(CAST(e.amount AS DECIMAL)), 0)
 		FROM expenses e
 		WHERE e.space_id = ? AND e.type = 'expense' AND e.date >= ? AND e.date <= ?
 		  AND EXISTS (SELECT 1 FROM expense_tags et WHERE et.expense_id = e.id AND et.tag_id IN (?))
 	`, spaceID, periodStart, periodEnd, tagIDs)
 	if err != nil {
-		return 0, err
+		return decimal.Zero, err
 	}
 	query = r.db.Rebind(query)
 
-	var spent int
+	var spent decimal.Decimal
 	err = r.db.Get(&spent, query, args...)
 	return spent, err
 }
@@ -142,8 +143,8 @@ func (r *budgetRepository) Update(budget *model.Budget, tagIDs []string) error {
 	}
 	defer tx.Rollback()
 
-	query := `UPDATE budgets SET amount_cents = $1, period = $2, start_date = $3, end_date = $4, is_active = $5, updated_at = $6 WHERE id = $7;`
-	_, err = tx.Exec(query, budget.AmountCents, budget.Period, budget.StartDate, budget.EndDate, budget.IsActive, budget.UpdatedAt, budget.ID)
+	query := `UPDATE budgets SET amount = $1, period = $2, start_date = $3, end_date = $4, is_active = $5, updated_at = $6 WHERE id = $7;`
+	_, err = tx.Exec(query, budget.Amount, budget.Period, budget.StartDate, budget.EndDate, budget.IsActive, budget.UpdatedAt, budget.ID)
 	if err != nil {
 		return err
 	}

internal/repository/expense.go

@@ -7,6 +7,7 @@ import (
 
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 var (
@@ -28,7 +29,7 @@ type ExpenseRepository interface {
 	GetDailySpending(spaceID string, from, to time.Time) ([]*model.DailySpending, error)
 	GetMonthlySpending(spaceID string, from, to time.Time) ([]*model.MonthlySpending, error)
 	GetTopExpenses(spaceID string, from, to time.Time, limit int) ([]*model.Expense, error)
-	GetIncomeVsExpenseSummary(spaceID string, from, to time.Time) (int, int, error)
+	GetIncomeVsExpenseSummary(spaceID string, from, to time.Time) (decimal.Decimal, decimal.Decimal, error)
 }
 
 type expenseRepository struct {
@@ -47,9 +48,9 @@ func (r *expenseRepository) Create(expense *model.Expense, tagIDs []string, item
 	defer tx.Rollback()
 
 	// Insert Expense
-	queryExpense := `INSERT INTO expenses (id, space_id, created_by, description, amount_cents, type, date, payment_method_id, recurring_expense_id, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11);`
-	_, err = tx.Exec(queryExpense, expense.ID, expense.SpaceID, expense.CreatedBy, expense.Description, expense.AmountCents, expense.Type, expense.Date, expense.PaymentMethodID, expense.RecurringExpenseID, expense.CreatedAt, expense.UpdatedAt)
+	queryExpense := `INSERT INTO expenses (id, space_id, created_by, description, amount, type, date, payment_method_id, recurring_expense_id, created_at, updated_at, amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, 0);`
+	_, err = tx.Exec(queryExpense, expense.ID, expense.SpaceID, expense.CreatedBy, expense.Description, expense.Amount, expense.Type, expense.Date, expense.PaymentMethodID, expense.RecurringExpenseID, expense.CreatedAt, expense.UpdatedAt)
 	if err != nil {
 		return err
 	}
@@ -122,7 +123,7 @@ func (r *expenseRepository) GetExpensesByTag(spaceID string, fromDate, toDate ti
 			t.id as tag_id,
 			t.name as tag_name,
 			t.color as tag_color,
-			SUM(e.amount_cents) as total_amount
+			SUM(CAST(e.amount AS DECIMAL)) as total_amount
 		FROM expenses e
 		JOIN expense_tags et ON e.id = et.expense_id
 		JOIN tags t ON et.tag_id = t.id
@@ -229,8 +230,8 @@ func (r *expenseRepository) Update(expense *model.Expense, tagIDs []string) erro
 	}
 	defer tx.Rollback()
 
-	query := `UPDATE expenses SET description = $1, amount_cents = $2, type = $3, date = $4, payment_method_id = $5, updated_at = $6 WHERE id = $7;`
-	_, err = tx.Exec(query, expense.Description, expense.AmountCents, expense.Type, expense.Date, expense.PaymentMethodID, expense.UpdatedAt, expense.ID)
+	query := `UPDATE expenses SET description = $1, amount = $2, type = $3, date = $4, payment_method_id = $5, updated_at = $6 WHERE id = $7;`
+	_, err = tx.Exec(query, expense.Description, expense.Amount, expense.Type, expense.Date, expense.PaymentMethodID, expense.UpdatedAt, expense.ID)
 	if err != nil {
 		return err
 	}
@@ -261,7 +262,7 @@ func (r *expenseRepository) Delete(id string) error {
 func (r *expenseRepository) GetDailySpending(spaceID string, from, to time.Time) ([]*model.DailySpending, error) {
 	var results []*model.DailySpending
 	query := `
-		SELECT date, SUM(amount_cents) as total_cents
+		SELECT date, SUM(CAST(amount AS DECIMAL)) as total
 		FROM expenses
 		WHERE space_id = $1 AND type = 'expense' AND date >= $2 AND date <= $3
 		GROUP BY date
@@ -276,14 +277,14 @@ func (r *expenseRepository) GetMonthlySpending(spaceID string, from, to time.Tim
 	var query string
 	if r.db.DriverName() == "sqlite" {
 		query = `
-			SELECT strftime('%Y-%m', date) as month, SUM(amount_cents) as total_cents
+			SELECT strftime('%Y-%m', date) as month, SUM(CAST(amount AS DECIMAL)) as total
 			FROM expenses
 			WHERE space_id = $1 AND type = 'expense' AND date >= $2 AND date <= $3
 			GROUP BY strftime('%Y-%m', date)
 			ORDER BY month ASC;`
 	} else {
 		query = `
-			SELECT TO_CHAR(date, 'YYYY-MM') as month, SUM(amount_cents) as total_cents
+			SELECT TO_CHAR(date, 'YYYY-MM') as month, SUM(CAST(amount AS DECIMAL)) as total
 			FROM expenses
 			WHERE space_id = $1 AND type = 'expense' AND date >= $2 AND date <= $3
 			GROUP BY TO_CHAR(date, 'YYYY-MM')
@@ -298,37 +299,38 @@ func (r *expenseRepository) GetTopExpenses(spaceID string, from, to time.Time, l
 	query := `
 		SELECT * FROM expenses
 		WHERE space_id = $1 AND type = 'expense' AND date >= $2 AND date <= $3
-		ORDER BY amount_cents DESC
+		ORDER BY CAST(amount AS DECIMAL) DESC
 		LIMIT $4;
 	`
 	err := r.db.Select(&results, query, spaceID, from, to, limit)
 	return results, err
 }
 
-func (r *expenseRepository) GetIncomeVsExpenseSummary(spaceID string, from, to time.Time) (int, int, error) {
+func (r *expenseRepository) GetIncomeVsExpenseSummary(spaceID string, from, to time.Time) (decimal.Decimal, decimal.Decimal, error) {
 	type summary struct {
 		Type  string          `db:"type"`
-		Total int    `db:"total"`
+		Total decimal.Decimal `db:"total"`
 	}
 	var results []summary
 	query := `
-		SELECT type, COALESCE(SUM(amount_cents), 0) as total
+		SELECT type, COALESCE(SUM(CAST(amount AS DECIMAL)), 0) as total
 		FROM expenses
 		WHERE space_id = $1 AND date >= $2 AND date <= $3
 		GROUP BY type;
 	`
 	err := r.db.Select(&results, query, spaceID, from, to)
 	if err != nil {
-		return 0, 0, err
+		return decimal.Zero, decimal.Zero, err
 	}
 
-	var income, expenses int
+	income := decimal.Zero
+	expenseTotal := decimal.Zero
 	for _, r := range results {
 		if r.Type == "topup" {
 			income = r.Total
 		} else if r.Type == "expense" {
-			expenses = r.Total
+			expenseTotal = r.Total
 		}
 	}
-	return income, expenses, nil
+	return income, expenseTotal, nil
 }

internal/repository/expense_test.go

@@ -7,6 +7,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/testutil"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -24,7 +25,7 @@ func TestExpenseRepository_Create(t *testing.T) {
 			SpaceID:     space.ID,
 			CreatedBy:   user.ID,
 			Description: "Lunch",
-			AmountCents: 1500,
+			Amount:      decimal.RequireFromString("15.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			CreatedAt:   now,
@@ -38,7 +39,7 @@ func TestExpenseRepository_Create(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, expense.ID, fetched.ID)
 		assert.Equal(t, "Lunch", fetched.Description)
-		assert.Equal(t, 1500, fetched.AmountCents)
+		assert.True(t, decimal.RequireFromString("15.00").Equal(fetched.Amount))
 		assert.Equal(t, model.ExpenseTypeExpense, fetched.Type)
 	})
 }
@@ -49,9 +50,9 @@ func TestExpenseRepository_GetBySpaceIDPaginated(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "test@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Test Space")
 
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 1", 1000, model.ExpenseTypeExpense)
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 2", 2000, model.ExpenseTypeExpense)
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 3", 3000, model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 1", decimal.RequireFromString("10.00"), model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 2", decimal.RequireFromString("20.00"), model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 3", decimal.RequireFromString("30.00"), model.ExpenseTypeExpense)
 
 		expenses, err := repo.GetBySpaceIDPaginated(space.ID, 2, 0)
 		require.NoError(t, err)
@@ -65,8 +66,8 @@ func TestExpenseRepository_CountBySpaceID(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "test@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Test Space")
 
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 1", 1000, model.ExpenseTypeExpense)
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 2", 2000, model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 1", decimal.RequireFromString("10.00"), model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Expense 2", decimal.RequireFromString("20.00"), model.ExpenseTypeExpense)
 
 		count, err := repo.CountBySpaceID(space.ID)
 		require.NoError(t, err)
@@ -87,7 +88,7 @@ func TestExpenseRepository_GetTagsByExpenseIDs(t *testing.T) {
 			SpaceID:     space.ID,
 			CreatedBy:   user.ID,
 			Description: "Weekly groceries",
-			AmountCents: 5000,
+			Amount:      decimal.RequireFromString("50.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			CreatedAt:   now,
@@ -119,7 +120,7 @@ func TestExpenseRepository_GetPaymentMethodsByExpenseIDs(t *testing.T) {
 			SpaceID:         space.ID,
 			CreatedBy:       user.ID,
 			Description:     "Online purchase",
-			AmountCents:     3000,
+			Amount:          decimal.RequireFromString("30.00"),
 			Type:            model.ExpenseTypeExpense,
 			Date:            now,
 			PaymentMethodID: &method.ID,
@@ -156,7 +157,7 @@ func TestExpenseRepository_GetExpensesByTag(t *testing.T) {
 			SpaceID:     space.ID,
 			CreatedBy:   user.ID,
 			Description: "Lunch",
-			AmountCents: 1500,
+			Amount:      decimal.RequireFromString("15.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			CreatedAt:   now,
@@ -170,7 +171,7 @@ func TestExpenseRepository_GetExpensesByTag(t *testing.T) {
 			SpaceID:     space.ID,
 			CreatedBy:   user.ID,
 			Description: "Dinner",
-			AmountCents: 2500,
+			Amount:      decimal.RequireFromString("25.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			CreatedAt:   now,
@@ -184,7 +185,7 @@ func TestExpenseRepository_GetExpensesByTag(t *testing.T) {
 		require.Len(t, summaries, 1)
 		assert.Equal(t, tag.ID, summaries[0].TagID)
 		assert.Equal(t, "Food", summaries[0].TagName)
-		assert.Equal(t, 4000, summaries[0].TotalAmount)
+		assert.True(t, decimal.RequireFromString("40.00").Equal(summaries[0].TotalAmount))
 	})
 }
 
@@ -202,7 +203,7 @@ func TestExpenseRepository_Update(t *testing.T) {
 			SpaceID:     space.ID,
 			CreatedBy:   user.ID,
 			Description: "Original",
-			AmountCents: 1000,
+			Amount:      decimal.RequireFromString("10.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			CreatedAt:   now,
@@ -234,7 +235,7 @@ func TestExpenseRepository_Delete(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "test@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Test Space")
 
-		expense := testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "To Delete", 500, model.ExpenseTypeExpense)
+		expense := testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "To Delete", decimal.RequireFromString("5.00"), model.ExpenseTypeExpense)
 
 		err := repo.Delete(expense.ID)
 		require.NoError(t, err)

internal/repository/loan.go

@@ -7,6 +7,7 @@ import (
 
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 var (
@@ -22,7 +23,7 @@ type LoanRepository interface {
 	Update(loan *model.Loan) error
 	Delete(id string) error
 	SetPaidOff(id string, paidOff bool) error
-	GetTotalPaidForLoan(loanID string) (int, error)
+	GetTotalPaidForLoan(loanID string) (decimal.Decimal, error)
 	GetReceiptCountForLoan(loanID string) (int, error)
 }
 
@@ -35,9 +36,9 @@ func NewLoanRepository(db *sqlx.DB) LoanRepository {
 }
 
 func (r *loanRepository) Create(loan *model.Loan) error {
-	query := `INSERT INTO loans (id, space_id, name, description, original_amount_cents, interest_rate_bps, start_date, end_date, is_paid_off, created_by, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12);`
-	_, err := r.db.Exec(query, loan.ID, loan.SpaceID, loan.Name, loan.Description, loan.OriginalAmountCents, loan.InterestRateBps, loan.StartDate, loan.EndDate, loan.IsPaidOff, loan.CreatedBy, loan.CreatedAt, loan.UpdatedAt)
+	query := `INSERT INTO loans (id, space_id, name, description, original_amount, interest_rate_bps, start_date, end_date, is_paid_off, created_by, created_at, updated_at, original_amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, 0);`
+	_, err := r.db.Exec(query, loan.ID, loan.SpaceID, loan.Name, loan.Description, loan.OriginalAmount, loan.InterestRateBps, loan.StartDate, loan.EndDate, loan.IsPaidOff, loan.CreatedBy, loan.CreatedAt, loan.UpdatedAt)
 	return err
 }
 
@@ -72,8 +73,8 @@ func (r *loanRepository) CountBySpaceID(spaceID string) (int, error) {
 }
 
 func (r *loanRepository) Update(loan *model.Loan) error {
-	query := `UPDATE loans SET name = $1, description = $2, original_amount_cents = $3, interest_rate_bps = $4, start_date = $5, end_date = $6, updated_at = $7 WHERE id = $8;`
-	result, err := r.db.Exec(query, loan.Name, loan.Description, loan.OriginalAmountCents, loan.InterestRateBps, loan.StartDate, loan.EndDate, loan.UpdatedAt, loan.ID)
+	query := `UPDATE loans SET name = $1, description = $2, original_amount = $3, interest_rate_bps = $4, start_date = $5, end_date = $6, updated_at = $7 WHERE id = $8;`
+	result, err := r.db.Exec(query, loan.Name, loan.Description, loan.OriginalAmount, loan.InterestRateBps, loan.StartDate, loan.EndDate, loan.UpdatedAt, loan.ID)
 	if err != nil {
 		return err
 	}
@@ -94,9 +95,9 @@ func (r *loanRepository) SetPaidOff(id string, paidOff bool) error {
 	return err
 }
 
-func (r *loanRepository) GetTotalPaidForLoan(loanID string) (int, error) {
-	var total int
-	err := r.db.Get(&total, `SELECT COALESCE(SUM(total_amount_cents), 0) FROM receipts WHERE loan_id = $1;`, loanID)
+func (r *loanRepository) GetTotalPaidForLoan(loanID string) (decimal.Decimal, error) {
+	var total decimal.Decimal
+	err := r.db.Get(&total, `SELECT COALESCE(SUM(CAST(total_amount AS DECIMAL)), 0) FROM receipts WHERE loan_id = $1;`, loanID)
 	return total, err
 }
 

internal/repository/money_account.go

@@ -7,6 +7,7 @@ import (
 
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 var (
@@ -25,8 +26,8 @@ type MoneyAccountRepository interface {
 	GetTransfersByAccountID(accountID string) ([]*model.AccountTransfer, error)
 	DeleteTransfer(id string) error
 
-	GetAccountBalance(accountID string) (int, error)
-	GetTotalAllocatedForSpace(spaceID string) (int, error)
+	GetAccountBalance(accountID string) (decimal.Decimal, error)
+	GetTotalAllocatedForSpace(spaceID string) (decimal.Decimal, error)
 
 	GetTransfersBySpaceIDPaginated(spaceID string, limit, offset int) ([]*model.AccountTransferWithAccount, error)
 	CountTransfersBySpaceID(spaceID string) (int, error)
@@ -94,8 +95,8 @@ func (r *moneyAccountRepository) Delete(id string) error {
 }
 
 func (r *moneyAccountRepository) CreateTransfer(transfer *model.AccountTransfer) error {
-	query := `INSERT INTO account_transfers (id, account_id, amount_cents, direction, note, recurring_deposit_id, created_by, created_at) VALUES ($1, $2, $3, $4, $5, $6, $7, $8);`
-	_, err := r.db.Exec(query, transfer.ID, transfer.AccountID, transfer.AmountCents, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt)
+	query := `INSERT INTO account_transfers (id, account_id, amount, direction, note, recurring_deposit_id, created_by, created_at, amount_cents) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, 0);`
+	_, err := r.db.Exec(query, transfer.ID, transfer.AccountID, transfer.Amount, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt)
 	return err
 }
 
@@ -122,16 +123,16 @@ func (r *moneyAccountRepository) DeleteTransfer(id string) error {
 	return err
 }
 
-func (r *moneyAccountRepository) GetAccountBalance(accountID string) (int, error) {
-	var balance int
-	query := `SELECT COALESCE(SUM(CASE WHEN direction = 'deposit' THEN amount_cents ELSE -amount_cents END), 0) FROM account_transfers WHERE account_id = $1;`
+func (r *moneyAccountRepository) GetAccountBalance(accountID string) (decimal.Decimal, error) {
+	var balance decimal.Decimal
+	query := `SELECT COALESCE(SUM(CASE WHEN direction = 'deposit' THEN CAST(amount AS DECIMAL) ELSE -CAST(amount AS DECIMAL) END), 0) FROM account_transfers WHERE account_id = $1;`
 	err := r.db.Get(&balance, query, accountID)
 	return balance, err
 }
 
-func (r *moneyAccountRepository) GetTotalAllocatedForSpace(spaceID string) (int, error) {
-	var total int
-	query := `SELECT COALESCE(SUM(CASE WHEN t.direction = 'deposit' THEN t.amount_cents ELSE -t.amount_cents END), 0)
+func (r *moneyAccountRepository) GetTotalAllocatedForSpace(spaceID string) (decimal.Decimal, error) {
+	var total decimal.Decimal
+	query := `SELECT COALESCE(SUM(CASE WHEN t.direction = 'deposit' THEN CAST(t.amount AS DECIMAL) ELSE -CAST(t.amount AS DECIMAL) END), 0)
 		FROM account_transfers t
 		JOIN money_accounts a ON t.account_id = a.id
 		WHERE a.space_id = $1;`
@@ -141,7 +142,7 @@ func (r *moneyAccountRepository) GetTotalAllocatedForSpace(spaceID string) (int,
 
 func (r *moneyAccountRepository) GetTransfersBySpaceIDPaginated(spaceID string, limit, offset int) ([]*model.AccountTransferWithAccount, error) {
 	var transfers []*model.AccountTransferWithAccount
-	query := `SELECT t.id, t.account_id, t.amount_cents, t.direction, t.note,
+	query := `SELECT t.id, t.account_id, t.amount, t.direction, t.note,
 		t.recurring_deposit_id, t.created_by, t.created_at, a.name AS account_name
 		FROM account_transfers t
 		JOIN money_accounts a ON t.account_id = a.id

internal/repository/money_account_test.go

@@ -7,6 +7,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/testutil"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -98,7 +99,7 @@ func TestMoneyAccountRepository_CreateTransfer(t *testing.T) {
 		transfer := &model.AccountTransfer{
 			ID:        uuid.NewString(),
 			AccountID: account.ID,
-			AmountCents: 5000,
+			Amount:    decimal.RequireFromString("50.00"),
 			Direction: model.TransferDirectionDeposit,
 			Note:      "Initial deposit",
 			CreatedBy: user.ID,
@@ -112,7 +113,7 @@ func TestMoneyAccountRepository_CreateTransfer(t *testing.T) {
 		require.NoError(t, err)
 		require.Len(t, transfers, 1)
 		assert.Equal(t, transfer.ID, transfers[0].ID)
-		assert.Equal(t, 5000, transfers[0].AmountCents)
+		assert.True(t, decimal.RequireFromString("50.00").Equal(transfers[0].Amount))
 		assert.Equal(t, model.TransferDirectionDeposit, transfers[0].Direction)
 	})
 }
@@ -123,7 +124,7 @@ func TestMoneyAccountRepository_DeleteTransfer(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "test@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Test Space")
 		account := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Checking", user.ID)
-		transfer := testutil.CreateTestTransfer(t, dbi.DB, account.ID, 1000, model.TransferDirectionDeposit, user.ID)
+		transfer := testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("10.00"), model.TransferDirectionDeposit, user.ID)
 
 		err := repo.DeleteTransfer(transfer.ID)
 		require.NoError(t, err)
@@ -141,12 +142,12 @@ func TestMoneyAccountRepository_GetAccountBalance(t *testing.T) {
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Test Space")
 		account := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Checking", user.ID)
 
-		testutil.CreateTestTransfer(t, dbi.DB, account.ID, 1000, model.TransferDirectionDeposit, user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account.ID, 300, model.TransferDirectionWithdrawal, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("10.00"), model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("3.00"), model.TransferDirectionWithdrawal, user.ID)
 
 		balance, err := repo.GetAccountBalance(account.ID)
 		require.NoError(t, err)
-		assert.Equal(t, 700, balance)
+		assert.True(t, decimal.RequireFromString("7.00").Equal(balance))
 	})
 }
 
@@ -159,11 +160,11 @@ func TestMoneyAccountRepository_GetTotalAllocatedForSpace(t *testing.T) {
 		account1 := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Account A", user.ID)
 		account2 := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Account B", user.ID)
 
-		testutil.CreateTestTransfer(t, dbi.DB, account1.ID, 2000, model.TransferDirectionDeposit, user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account2.ID, 3000, model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account1.ID, decimal.RequireFromString("20.00"), model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account2.ID, decimal.RequireFromString("30.00"), model.TransferDirectionDeposit, user.ID)
 
 		total, err := repo.GetTotalAllocatedForSpace(space.ID)
 		require.NoError(t, err)
-		assert.Equal(t, 5000, total)
+		assert.True(t, decimal.RequireFromString("50.00").Equal(total))
 	})
 }

internal/repository/receipt.go

@@ -6,6 +6,7 @@ import (
 
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 var (
@@ -57,9 +58,9 @@ func (r *receiptRepository) CreateWithSources(
 
 	// Insert receipt
 	_, err = tx.Exec(
-		`INSERT INTO receipts (id, loan_id, space_id, description, total_amount_cents, date, recurring_receipt_id, created_by, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10);`,
-		receipt.ID, receipt.LoanID, receipt.SpaceID, receipt.Description, receipt.TotalAmountCents, receipt.Date, receipt.RecurringReceiptID, receipt.CreatedBy, receipt.CreatedAt, receipt.UpdatedAt,
+		`INSERT INTO receipts (id, loan_id, space_id, description, total_amount, date, recurring_receipt_id, created_by, created_at, updated_at, total_amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, 0);`,
+		receipt.ID, receipt.LoanID, receipt.SpaceID, receipt.Description, receipt.TotalAmount, receipt.Date, receipt.RecurringReceiptID, receipt.CreatedBy, receipt.CreatedAt, receipt.UpdatedAt,
 	)
 	if err != nil {
 		return err
@@ -68,9 +69,9 @@ func (r *receiptRepository) CreateWithSources(
 	// Insert balance expense if present
 	if balanceExpense != nil {
 		_, err = tx.Exec(
-			`INSERT INTO expenses (id, space_id, created_by, description, amount_cents, type, date, payment_method_id, recurring_expense_id, created_at, updated_at)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11);`,
-			balanceExpense.ID, balanceExpense.SpaceID, balanceExpense.CreatedBy, balanceExpense.Description, balanceExpense.AmountCents, balanceExpense.Type, balanceExpense.Date, balanceExpense.PaymentMethodID, balanceExpense.RecurringExpenseID, balanceExpense.CreatedAt, balanceExpense.UpdatedAt,
+			`INSERT INTO expenses (id, space_id, created_by, description, amount, type, date, payment_method_id, recurring_expense_id, created_at, updated_at, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, 0);`,
+			balanceExpense.ID, balanceExpense.SpaceID, balanceExpense.CreatedBy, balanceExpense.Description, balanceExpense.Amount, balanceExpense.Type, balanceExpense.Date, balanceExpense.PaymentMethodID, balanceExpense.RecurringExpenseID, balanceExpense.CreatedAt, balanceExpense.UpdatedAt,
 		)
 		if err != nil {
 			return err
@@ -80,9 +81,9 @@ func (r *receiptRepository) CreateWithSources(
 	// Insert account transfers
 	for _, transfer := range accountTransfers {
 		_, err = tx.Exec(
-			`INSERT INTO account_transfers (id, account_id, amount_cents, direction, note, recurring_deposit_id, created_by, created_at)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8);`,
-			transfer.ID, transfer.AccountID, transfer.AmountCents, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt,
+			`INSERT INTO account_transfers (id, account_id, amount, direction, note, recurring_deposit_id, created_by, created_at, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, 0);`,
+			transfer.ID, transfer.AccountID, transfer.Amount, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt,
 		)
 		if err != nil {
 			return err
@@ -92,9 +93,9 @@ func (r *receiptRepository) CreateWithSources(
 	// Insert funding sources
 	for _, src := range sources {
 		_, err = tx.Exec(
-			`INSERT INTO receipt_funding_sources (id, receipt_id, source_type, account_id, amount_cents, linked_expense_id, linked_transfer_id)
-			VALUES ($1, $2, $3, $4, $5, $6, $7);`,
-			src.ID, src.ReceiptID, src.SourceType, src.AccountID, src.AmountCents, src.LinkedExpenseID, src.LinkedTransferID,
+			`INSERT INTO receipt_funding_sources (id, receipt_id, source_type, account_id, amount, linked_expense_id, linked_transfer_id, amount_cents)
+			Values ($1, $2, $3, $4, $5, $6, $7, 0);`,
+			src.ID, src.ReceiptID, src.SourceType, src.AccountID, src.Amount, src.LinkedExpenseID, src.LinkedTransferID,
 		)
 		if err != nil {
 			return err
@@ -157,14 +158,14 @@ func (r *receiptRepository) GetFundingSourcesWithAccountsByReceiptIDs(receiptIDs
 		ReceiptID        string                  `db:"receipt_id"`
 		SourceType       model.FundingSourceType `db:"source_type"`
 		AccountID        *string                 `db:"account_id"`
-		AmountCents      int                     `db:"amount_cents"`
+		Amount           decimal.Decimal         `db:"amount"`
 		LinkedExpenseID  *string                 `db:"linked_expense_id"`
 		LinkedTransferID *string                 `db:"linked_transfer_id"`
 		AccountName      *string                 `db:"account_name"`
 	}
 
 	query, args, err := sqlx.In(`
-		SELECT rfs.id, rfs.receipt_id, rfs.source_type, rfs.account_id, rfs.amount_cents,
+		SELECT rfs.id, rfs.receipt_id, rfs.source_type, rfs.account_id, rfs.amount,
 			rfs.linked_expense_id, rfs.linked_transfer_id,
 			ma.name AS account_name
 		FROM receipt_funding_sources rfs
@@ -194,7 +195,7 @@ func (r *receiptRepository) GetFundingSourcesWithAccountsByReceiptIDs(receiptIDs
 				ReceiptID:        rw.ReceiptID,
 				SourceType:       rw.SourceType,
 				AccountID:        rw.AccountID,
-				AmountCents:      rw.AmountCents,
+				Amount:           rw.Amount,
 				LinkedExpenseID:  rw.LinkedExpenseID,
 				LinkedTransferID: rw.LinkedTransferID,
 			},
@@ -279,8 +280,8 @@ func (r *receiptRepository) UpdateWithSources(
 
 	// Update receipt
 	_, err = tx.Exec(
-		`UPDATE receipts SET description = $1, total_amount_cents = $2, date = $3, updated_at = $4 WHERE id = $5;`,
-		receipt.Description, receipt.TotalAmountCents, receipt.Date, receipt.UpdatedAt, receipt.ID,
+		`UPDATE receipts SET description = $1, total_amount = $2, date = $3, updated_at = $4 WHERE id = $5;`,
+		receipt.Description, receipt.TotalAmount, receipt.Date, receipt.UpdatedAt, receipt.ID,
 	)
 	if err != nil {
 		return err
@@ -289,9 +290,9 @@ func (r *receiptRepository) UpdateWithSources(
 	// Insert new balance expense
 	if balanceExpense != nil {
 		_, err = tx.Exec(
-			`INSERT INTO expenses (id, space_id, created_by, description, amount_cents, type, date, payment_method_id, recurring_expense_id, created_at, updated_at)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11);`,
-			balanceExpense.ID, balanceExpense.SpaceID, balanceExpense.CreatedBy, balanceExpense.Description, balanceExpense.AmountCents, balanceExpense.Type, balanceExpense.Date, balanceExpense.PaymentMethodID, balanceExpense.RecurringExpenseID, balanceExpense.CreatedAt, balanceExpense.UpdatedAt,
+			`INSERT INTO expenses (id, space_id, created_by, description, amount, type, date, payment_method_id, recurring_expense_id, created_at, updated_at, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, 0);`,
+			balanceExpense.ID, balanceExpense.SpaceID, balanceExpense.CreatedBy, balanceExpense.Description, balanceExpense.Amount, balanceExpense.Type, balanceExpense.Date, balanceExpense.PaymentMethodID, balanceExpense.RecurringExpenseID, balanceExpense.CreatedAt, balanceExpense.UpdatedAt,
 		)
 		if err != nil {
 			return err
@@ -301,9 +302,9 @@ func (r *receiptRepository) UpdateWithSources(
 	// Insert new account transfers
 	for _, transfer := range accountTransfers {
 		_, err = tx.Exec(
-			`INSERT INTO account_transfers (id, account_id, amount_cents, direction, note, recurring_deposit_id, created_by, created_at)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8);`,
-			transfer.ID, transfer.AccountID, transfer.AmountCents, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt,
+			`INSERT INTO account_transfers (id, account_id, amount, direction, note, recurring_deposit_id, created_by, created_at, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, 0);`,
+			transfer.ID, transfer.AccountID, transfer.Amount, transfer.Direction, transfer.Note, transfer.RecurringDepositID, transfer.CreatedBy, transfer.CreatedAt,
 		)
 		if err != nil {
 			return err
@@ -313,9 +314,9 @@ func (r *receiptRepository) UpdateWithSources(
 	// Insert new funding sources
 	for _, src := range sources {
 		_, err = tx.Exec(
-			`INSERT INTO receipt_funding_sources (id, receipt_id, source_type, account_id, amount_cents, linked_expense_id, linked_transfer_id)
-			VALUES ($1, $2, $3, $4, $5, $6, $7);`,
-			src.ID, src.ReceiptID, src.SourceType, src.AccountID, src.AmountCents, src.LinkedExpenseID, src.LinkedTransferID,
+			`INSERT INTO receipt_funding_sources (id, receipt_id, source_type, account_id, amount, linked_expense_id, linked_transfer_id, amount_cents)
+			Values ($1, $2, $3, $4, $5, $6, $7, 0);`,
+			src.ID, src.ReceiptID, src.SourceType, src.AccountID, src.Amount, src.LinkedExpenseID, src.LinkedTransferID,
 		)
 		if err != nil {
 			return err

internal/repository/recurring_deposit.go

@@ -35,9 +35,9 @@ func NewRecurringDepositRepository(db *sqlx.DB) RecurringDepositRepository {
 }
 
 func (r *recurringDepositRepository) Create(rd *model.RecurringDeposit) error {
-	query := `INSERT INTO recurring_deposits (id, space_id, account_id, amount_cents, frequency, start_date, end_date, next_occurrence, is_active, title, created_by, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13);`
-	_, err := r.db.Exec(query, rd.ID, rd.SpaceID, rd.AccountID, rd.AmountCents, rd.Frequency, rd.StartDate, rd.EndDate, rd.NextOccurrence, rd.IsActive, rd.Title, rd.CreatedBy, rd.CreatedAt, rd.UpdatedAt)
+	query := `INSERT INTO recurring_deposits (id, space_id, account_id, amount, frequency, start_date, end_date, next_occurrence, is_active, title, created_by, created_at, updated_at, amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, 0);`
+	_, err := r.db.Exec(query, rd.ID, rd.SpaceID, rd.AccountID, rd.Amount, rd.Frequency, rd.StartDate, rd.EndDate, rd.NextOccurrence, rd.IsActive, rd.Title, rd.CreatedBy, rd.CreatedAt, rd.UpdatedAt)
 	return err
 }
 
@@ -59,8 +59,8 @@ func (r *recurringDepositRepository) GetBySpaceID(spaceID string) ([]*model.Recu
 }
 
 func (r *recurringDepositRepository) Update(rd *model.RecurringDeposit) error {
-	query := `UPDATE recurring_deposits SET account_id = $1, amount_cents = $2, frequency = $3, start_date = $4, end_date = $5, next_occurrence = $6, title = $7, updated_at = $8 WHERE id = $9;`
-	result, err := r.db.Exec(query, rd.AccountID, rd.AmountCents, rd.Frequency, rd.StartDate, rd.EndDate, rd.NextOccurrence, rd.Title, rd.UpdatedAt, rd.ID)
+	query := `UPDATE recurring_deposits SET account_id = $1, amount = $2, frequency = $3, start_date = $4, end_date = $5, next_occurrence = $6, title = $7, updated_at = $8 WHERE id = $9;`
+	result, err := r.db.Exec(query, rd.AccountID, rd.Amount, rd.Frequency, rd.StartDate, rd.EndDate, rd.NextOccurrence, rd.Title, rd.UpdatedAt, rd.ID)
 	if err != nil {
 		return err
 	}

internal/repository/recurring_expense.go

@@ -43,9 +43,9 @@ func (r *recurringExpenseRepository) Create(re *model.RecurringExpense, tagIDs [
 	}
 	defer tx.Rollback()
 
-	query := `INSERT INTO recurring_expenses (id, space_id, created_by, description, amount_cents, type, payment_method_id, frequency, start_date, end_date, next_occurrence, is_active, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14);`
-	_, err = tx.Exec(query, re.ID, re.SpaceID, re.CreatedBy, re.Description, re.AmountCents, re.Type, re.PaymentMethodID, re.Frequency, re.StartDate, re.EndDate, re.NextOccurrence, re.IsActive, re.CreatedAt, re.UpdatedAt)
+	query := `INSERT INTO recurring_expenses (id, space_id, created_by, description, amount, type, payment_method_id, frequency, start_date, end_date, next_occurrence, is_active, created_at, updated_at, amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, 0);`
+	_, err = tx.Exec(query, re.ID, re.SpaceID, re.CreatedBy, re.Description, re.Amount, re.Type, re.PaymentMethodID, re.Frequency, re.StartDate, re.EndDate, re.NextOccurrence, re.IsActive, re.CreatedAt, re.UpdatedAt)
 	if err != nil {
 		return err
 	}
@@ -171,8 +171,8 @@ func (r *recurringExpenseRepository) Update(re *model.RecurringExpense, tagIDs [
 	}
 	defer tx.Rollback()
 
-	query := `UPDATE recurring_expenses SET description = $1, amount_cents = $2, type = $3, payment_method_id = $4, frequency = $5, start_date = $6, end_date = $7, next_occurrence = $8, updated_at = $9 WHERE id = $10;`
-	_, err = tx.Exec(query, re.Description, re.AmountCents, re.Type, re.PaymentMethodID, re.Frequency, re.StartDate, re.EndDate, re.NextOccurrence, re.UpdatedAt, re.ID)
+	query := `UPDATE recurring_expenses SET description = $1, amount = $2, type = $3, payment_method_id = $4, frequency = $5, start_date = $6, end_date = $7, next_occurrence = $8, updated_at = $9 WHERE id = $10;`
+	_, err = tx.Exec(query, re.Description, re.Amount, re.Type, re.PaymentMethodID, re.Frequency, re.StartDate, re.EndDate, re.NextOccurrence, re.UpdatedAt, re.ID)
 	if err != nil {
 		return err
 	}

internal/repository/recurring_receipt.go

@@ -44,9 +44,9 @@ func (r *recurringReceiptRepository) Create(rr *model.RecurringReceipt, sources
 	defer tx.Rollback()
 
 	_, err = tx.Exec(
-		`INSERT INTO recurring_receipts (id, loan_id, space_id, description, total_amount_cents, frequency, start_date, end_date, next_occurrence, is_active, created_by, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13);`,
-		rr.ID, rr.LoanID, rr.SpaceID, rr.Description, rr.TotalAmountCents, rr.Frequency, rr.StartDate, rr.EndDate, rr.NextOccurrence, rr.IsActive, rr.CreatedBy, rr.CreatedAt, rr.UpdatedAt,
+		`INSERT INTO recurring_receipts (id, loan_id, space_id, description, total_amount, frequency, start_date, end_date, next_occurrence, is_active, created_by, created_at, updated_at, total_amount_cents)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, 0);`,
+		rr.ID, rr.LoanID, rr.SpaceID, rr.Description, rr.TotalAmount, rr.Frequency, rr.StartDate, rr.EndDate, rr.NextOccurrence, rr.IsActive, rr.CreatedBy, rr.CreatedAt, rr.UpdatedAt,
 	)
 	if err != nil {
 		return err
@@ -54,9 +54,9 @@ func (r *recurringReceiptRepository) Create(rr *model.RecurringReceipt, sources
 
 	for _, src := range sources {
 		_, err = tx.Exec(
-			`INSERT INTO recurring_receipt_sources (id, recurring_receipt_id, source_type, account_id, amount_cents)
-			VALUES ($1, $2, $3, $4, $5);`,
-			src.ID, src.RecurringReceiptID, src.SourceType, src.AccountID, src.AmountCents,
+			`INSERT INTO recurring_receipt_sources (id, recurring_receipt_id, source_type, account_id, amount, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, 0);`,
+			src.ID, src.RecurringReceiptID, src.SourceType, src.AccountID, src.Amount,
 		)
 		if err != nil {
 			return err
@@ -105,8 +105,8 @@ func (r *recurringReceiptRepository) Update(rr *model.RecurringReceipt, sources
 	defer tx.Rollback()
 
 	_, err = tx.Exec(
-		`UPDATE recurring_receipts SET description = $1, total_amount_cents = $2, frequency = $3, start_date = $4, end_date = $5, next_occurrence = $6, updated_at = $7 WHERE id = $8;`,
-		rr.Description, rr.TotalAmountCents, rr.Frequency, rr.StartDate, rr.EndDate, rr.NextOccurrence, rr.UpdatedAt, rr.ID,
+		`UPDATE recurring_receipts SET description = $1, total_amount = $2, frequency = $3, start_date = $4, end_date = $5, next_occurrence = $6, updated_at = $7 WHERE id = $8;`,
+		rr.Description, rr.TotalAmount, rr.Frequency, rr.StartDate, rr.EndDate, rr.NextOccurrence, rr.UpdatedAt, rr.ID,
 	)
 	if err != nil {
 		return err
@@ -119,9 +119,9 @@ func (r *recurringReceiptRepository) Update(rr *model.RecurringReceipt, sources
 
 	for _, src := range sources {
 		_, err = tx.Exec(
-			`INSERT INTO recurring_receipt_sources (id, recurring_receipt_id, source_type, account_id, amount_cents)
-			VALUES ($1, $2, $3, $4, $5);`,
-			src.ID, src.RecurringReceiptID, src.SourceType, src.AccountID, src.AmountCents,
+			`INSERT INTO recurring_receipt_sources (id, recurring_receipt_id, source_type, account_id, amount, amount_cents)
+			VALUES ($1, $2, $3, $4, $5, 0);`,
+			src.ID, src.RecurringReceiptID, src.SourceType, src.AccountID, src.Amount,
 		)
 		if err != nil {
 			return err

internal/service/budget.go

@@ -7,12 +7,13 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateBudgetDTO struct {
 	SpaceID   string
 	TagIDs    []string
-	Amount    int
+	Amount    decimal.Decimal
 	Period    model.BudgetPeriod
 	StartDate time.Time
 	EndDate   *time.Time
@@ -22,7 +23,7 @@ type CreateBudgetDTO struct {
 type UpdateBudgetDTO struct {
 	ID        string
 	TagIDs    []string
-	Amount    int
+	Amount    decimal.Decimal
 	Period    model.BudgetPeriod
 	StartDate time.Time
 	EndDate   *time.Time
@@ -37,7 +38,7 @@ func NewBudgetService(budgetRepo repository.BudgetRepository) *BudgetService {
 }
 
 func (s *BudgetService) CreateBudget(dto CreateBudgetDTO) (*model.Budget, error) {
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("budget amount must be positive")
 	}
 
@@ -49,7 +50,7 @@ func (s *BudgetService) CreateBudget(dto CreateBudgetDTO) (*model.Budget, error)
 	budget := &model.Budget{
 		ID:        uuid.NewString(),
 		SpaceID:   dto.SpaceID,
-		AmountCents: dto.Amount,
+		Amount:    dto.Amount,
 		Period:    dto.Period,
 		StartDate: dto.StartDate,
 		EndDate:   dto.EndDate,
@@ -99,12 +100,12 @@ func (s *BudgetService) GetBudgetsWithSpent(spaceID string) ([]*model.BudgetWith
 		start, end := GetCurrentPeriodBounds(b.Period, time.Now())
 		spent, err := s.budgetRepo.GetSpentForBudget(spaceID, tagIDs, start, end)
 		if err != nil {
-			spent = 0
+			spent = decimal.Zero
 		}
 
 		var percentage float64
-		if b.AmountCents > 0 {
-			percentage = float64(spent) / float64(b.AmountCents) * 100
+		if b.Amount.GreaterThan(decimal.Zero) {
+			percentage, _ = spent.Div(b.Amount).Mul(decimal.NewFromInt(100)).Float64()
 		}
 
 		var status model.BudgetStatus
@@ -120,7 +121,7 @@ func (s *BudgetService) GetBudgetsWithSpent(spaceID string) ([]*model.BudgetWith
 		bws := &model.BudgetWithSpent{
 			Budget:     *b,
 			Tags:       tags,
-			SpentCents: spent,
+			Spent:      spent,
 			Percentage: percentage,
 			Status:     status,
 		}
@@ -131,7 +132,7 @@ func (s *BudgetService) GetBudgetsWithSpent(spaceID string) ([]*model.BudgetWith
 }
 
 func (s *BudgetService) UpdateBudget(dto UpdateBudgetDTO) (*model.Budget, error) {
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("budget amount must be positive")
 	}
 
@@ -144,7 +145,7 @@ func (s *BudgetService) UpdateBudget(dto UpdateBudgetDTO) (*model.Budget, error)
 		return nil, err
 	}
 
-	existing.AmountCents = dto.Amount
+	existing.Amount = dto.Amount
 	existing.Period = dto.Period
 	existing.StartDate = dto.StartDate
 	existing.EndDate = dto.EndDate

internal/service/expense.go

@@ -7,13 +7,14 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateExpenseDTO struct {
 	SpaceID         string
 	UserID          string
 	Description     string
-	Amount          int
+	Amount          decimal.Decimal
 	Type            model.ExpenseType
 	Date            time.Time
 	TagIDs          []string
@@ -25,7 +26,7 @@ type UpdateExpenseDTO struct {
 	ID              string
 	SpaceID         string
 	Description     string
-	Amount          int
+	Amount          decimal.Decimal
 	Type            model.ExpenseType
 	Date            time.Time
 	TagIDs          []string
@@ -48,7 +49,7 @@ func (s *ExpenseService) CreateExpense(dto CreateExpenseDTO) (*model.Expense, er
 	if dto.Description == "" {
 		return nil, fmt.Errorf("expense description cannot be empty")
 	}
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -58,7 +59,7 @@ func (s *ExpenseService) CreateExpense(dto CreateExpenseDTO) (*model.Expense, er
 		SpaceID:         dto.SpaceID,
 		CreatedBy:       dto.UserID,
 		Description:     dto.Description,
-		AmountCents:     dto.Amount,
+		Amount:          dto.Amount,
 		Type:            dto.Type,
 		Date:            dto.Date,
 		PaymentMethodID: dto.PaymentMethodID,
@@ -78,18 +79,18 @@ func (s *ExpenseService) GetExpensesForSpace(spaceID string) ([]*model.Expense,
 	return s.expenseRepo.GetBySpaceID(spaceID)
 }
 
-func (s *ExpenseService) GetBalanceForSpace(spaceID string) (int, error) {
+func (s *ExpenseService) GetBalanceForSpace(spaceID string) (decimal.Decimal, error) {
 	expenses, err := s.expenseRepo.GetBySpaceID(spaceID)
 	if err != nil {
-		return 0, err
+		return decimal.Zero, err
 	}
 
-	var balance int
+	balance := decimal.Zero
 	for _, expense := range expenses {
 		if expense.Type == model.ExpenseTypeExpense {
-			balance -= expense.AmountCents
+			balance = balance.Sub(expense.Amount)
 		} else if expense.Type == model.ExpenseTypeTopup {
-			balance += expense.AmountCents
+			balance = balance.Add(expense.Amount)
 		}
 	}
 
@@ -234,7 +235,7 @@ func (s *ExpenseService) UpdateExpense(dto UpdateExpenseDTO) (*model.Expense, er
 	if dto.Description == "" {
 		return nil, fmt.Errorf("expense description cannot be empty")
 	}
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -244,7 +245,7 @@ func (s *ExpenseService) UpdateExpense(dto UpdateExpenseDTO) (*model.Expense, er
 	}
 
 	existing.Description = dto.Description
-	existing.AmountCents = dto.Amount
+	existing.Amount = dto.Amount
 	existing.Type = dto.Type
 	existing.Date = dto.Date
 	existing.PaymentMethodID = dto.PaymentMethodID

internal/service/expense_test.go

@@ -7,6 +7,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"git.juancwu.dev/juancwu/budgit/internal/testutil"
+	"github.com/shopspring/decimal"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -24,7 +25,7 @@ func TestExpenseService_CreateExpense(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Lunch",
-			Amount:      1500,
+			Amount:      decimal.RequireFromString("15.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 			TagIDs:      []string{tag.ID},
@@ -32,7 +33,7 @@ func TestExpenseService_CreateExpense(t *testing.T) {
 		require.NoError(t, err)
 		assert.NotEmpty(t, expense.ID)
 		assert.Equal(t, "Lunch", expense.Description)
-		assert.Equal(t, 1500, expense.AmountCents)
+		assert.True(t, decimal.RequireFromString("15.00").Equal(expense.Amount))
 		assert.Equal(t, model.ExpenseTypeExpense, expense.Type)
 	})
 }
@@ -46,7 +47,7 @@ func TestExpenseService_CreateExpense_EmptyDescription(t *testing.T) {
 			SpaceID:     "some-space",
 			UserID:      "some-user",
 			Description: "",
-			Amount:      1000,
+			Amount:      decimal.RequireFromString("10.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})
@@ -64,7 +65,7 @@ func TestExpenseService_CreateExpense_ZeroAmount(t *testing.T) {
 			SpaceID:     "some-space",
 			UserID:      "some-user",
 			Description: "Something",
-			Amount:      0,
+			Amount:      decimal.Zero,
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})
@@ -87,7 +88,7 @@ func TestExpenseService_GetExpensesWithTagsForSpacePaginated(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Bus fare",
-			Amount:      250,
+			Amount:      decimal.RequireFromString("2.50"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 			TagIDs:      []string{tag.ID},
@@ -99,7 +100,7 @@ func TestExpenseService_GetExpensesWithTagsForSpacePaginated(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Coffee",
-			Amount:      500,
+			Amount:      decimal.RequireFromString("5.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})
@@ -132,12 +133,12 @@ func TestExpenseService_GetBalanceForSpace(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "exp-svc-balance@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Expense Svc Balance Space")
 
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Topup", 10000, model.ExpenseTypeTopup)
-		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Groceries", 3000, model.ExpenseTypeExpense)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Topup", decimal.RequireFromString("100.00"), model.ExpenseTypeTopup)
+		testutil.CreateTestExpense(t, dbi.DB, space.ID, user.ID, "Groceries", decimal.RequireFromString("30.00"), model.ExpenseTypeExpense)
 
 		balance, err := svc.GetBalanceForSpace(space.ID)
 		require.NoError(t, err)
-		assert.Equal(t, 7000, balance)
+		assert.True(t, decimal.RequireFromString("70.00").Equal(balance))
 	})
 }
 
@@ -156,7 +157,7 @@ func TestExpenseService_GetExpensesByTag(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Dinner",
-			Amount:      2500,
+			Amount:      decimal.RequireFromString("25.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        now,
 			TagIDs:      []string{tag.ID},
@@ -169,7 +170,7 @@ func TestExpenseService_GetExpensesByTag(t *testing.T) {
 		require.NoError(t, err)
 		require.Len(t, summaries, 1)
 		assert.Equal(t, tag.ID, summaries[0].TagID)
-		assert.Equal(t, 2500, summaries[0].TotalAmount)
+		assert.True(t, decimal.RequireFromString("25.00").Equal(summaries[0].TotalAmount))
 	})
 }
 
@@ -185,7 +186,7 @@ func TestExpenseService_UpdateExpense(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Old Description",
-			Amount:      1000,
+			Amount:      decimal.RequireFromString("10.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})
@@ -195,13 +196,13 @@ func TestExpenseService_UpdateExpense(t *testing.T) {
 			ID:          created.ID,
 			SpaceID:     space.ID,
 			Description: "New Description",
-			Amount:      2000,
+			Amount:      decimal.RequireFromString("20.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})
 		require.NoError(t, err)
 		assert.Equal(t, "New Description", updated.Description)
-		assert.Equal(t, 2000, updated.AmountCents)
+		assert.True(t, decimal.RequireFromString("20.00").Equal(updated.Amount))
 	})
 }
 
@@ -217,7 +218,7 @@ func TestExpenseService_DeleteExpense(t *testing.T) {
 			SpaceID:     space.ID,
 			UserID:      user.ID,
 			Description: "Doomed Expense",
-			Amount:      500,
+			Amount:      decimal.RequireFromString("5.00"),
 			Type:        model.ExpenseTypeExpense,
 			Date:        time.Now(),
 		})

internal/service/loan.go

@@ -7,6 +7,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateLoanDTO struct {
@@ -14,7 +15,7 @@ type CreateLoanDTO struct {
 	UserID          string
 	Name            string
 	Description     string
-	OriginalAmount  int
+	OriginalAmount  decimal.Decimal
 	InterestRateBps int
 	StartDate       time.Time
 	EndDate         *time.Time
@@ -24,7 +25,7 @@ type UpdateLoanDTO struct {
 	ID              string
 	Name            string
 	Description     string
-	OriginalAmount  int
+	OriginalAmount  decimal.Decimal
 	InterestRateBps int
 	StartDate       time.Time
 	EndDate         *time.Time
@@ -48,7 +49,7 @@ func (s *LoanService) CreateLoan(dto CreateLoanDTO) (*model.Loan, error) {
 	if dto.Name == "" {
 		return nil, fmt.Errorf("loan name cannot be empty")
 	}
-	if dto.OriginalAmount <= 0 {
+	if dto.OriginalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -58,7 +59,7 @@ func (s *LoanService) CreateLoan(dto CreateLoanDTO) (*model.Loan, error) {
 		SpaceID:         dto.SpaceID,
 		Name:            dto.Name,
 		Description:     dto.Description,
-		OriginalAmountCents: dto.OriginalAmount,
+		OriginalAmount:  dto.OriginalAmount,
 		InterestRateBps: dto.InterestRateBps,
 		StartDate:       dto.StartDate,
 		EndDate:         dto.EndDate,
@@ -96,8 +97,8 @@ func (s *LoanService) GetLoanWithSummary(id string) (*model.LoanWithPaymentSumma
 
 	return &model.LoanWithPaymentSummary{
 		Loan:         *loan,
-		TotalPaidCents: totalPaid,
-		RemainingCents: loan.OriginalAmountCents - totalPaid,
+		TotalPaid:    totalPaid,
+		Remaining:    loan.OriginalAmount.Sub(totalPaid),
 		ReceiptCount: receiptCount,
 	}, nil
 }
@@ -155,8 +156,8 @@ func (s *LoanService) attachSummaries(loans []*model.Loan) ([]*model.LoanWithPay
 		}
 		result[i] = &model.LoanWithPaymentSummary{
 			Loan:         *loan,
-			TotalPaidCents: totalPaid,
-			RemainingCents: loan.OriginalAmountCents - totalPaid,
+			TotalPaid:    totalPaid,
+			Remaining:    loan.OriginalAmount.Sub(totalPaid),
 			ReceiptCount: receiptCount,
 		}
 	}
@@ -167,7 +168,7 @@ func (s *LoanService) UpdateLoan(dto UpdateLoanDTO) (*model.Loan, error) {
 	if dto.Name == "" {
 		return nil, fmt.Errorf("loan name cannot be empty")
 	}
-	if dto.OriginalAmount <= 0 {
+	if dto.OriginalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -178,7 +179,7 @@ func (s *LoanService) UpdateLoan(dto UpdateLoanDTO) (*model.Loan, error) {
 
 	existing.Name = dto.Name
 	existing.Description = dto.Description
-	existing.OriginalAmountCents = dto.OriginalAmount
+	existing.OriginalAmount = dto.OriginalAmount
 	existing.InterestRateBps = dto.InterestRateBps
 	existing.StartDate = dto.StartDate
 	existing.EndDate = dto.EndDate

internal/service/money_account.go

@@ -8,6 +8,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateMoneyAccountDTO struct {
@@ -23,7 +24,7 @@ type UpdateMoneyAccountDTO struct {
 
 type CreateTransferDTO struct {
 	AccountID string
-	Amount    int
+	Amount    decimal.Decimal
 	Direction model.TransferDirection
 	Note      string
 	CreatedBy string
@@ -77,7 +78,7 @@ func (s *MoneyAccountService) GetAccountsForSpace(spaceID string) ([]model.Money
 		}
 		result[i] = model.MoneyAccountWithBalance{
 			MoneyAccount: *acct,
-			BalanceCents: balance,
+			Balance:      balance,
 		}
 	}
 
@@ -113,8 +114,8 @@ func (s *MoneyAccountService) DeleteAccount(id string) error {
 	return s.accountRepo.Delete(id)
 }
 
-func (s *MoneyAccountService) CreateTransfer(dto CreateTransferDTO, availableSpaceBalance int) (*model.AccountTransfer, error) {
-	if dto.Amount <= 0 {
+func (s *MoneyAccountService) CreateTransfer(dto CreateTransferDTO, availableSpaceBalance decimal.Decimal) (*model.AccountTransfer, error) {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -123,7 +124,7 @@ func (s *MoneyAccountService) CreateTransfer(dto CreateTransferDTO, availableSpa
 	}
 
 	if dto.Direction == model.TransferDirectionDeposit {
-		if dto.Amount > availableSpaceBalance {
+		if dto.Amount.GreaterThan(availableSpaceBalance) {
 			return nil, fmt.Errorf("insufficient available balance")
 		}
 	}
@@ -133,7 +134,7 @@ func (s *MoneyAccountService) CreateTransfer(dto CreateTransferDTO, availableSpa
 		if err != nil {
 			return nil, err
 		}
-		if dto.Amount > accountBalance {
+		if dto.Amount.GreaterThan(accountBalance) {
 			return nil, fmt.Errorf("insufficient account balance")
 		}
 	}
@@ -141,7 +142,7 @@ func (s *MoneyAccountService) CreateTransfer(dto CreateTransferDTO, availableSpa
 	transfer := &model.AccountTransfer{
 		ID:        uuid.NewString(),
 		AccountID: dto.AccountID,
-		AmountCents: dto.Amount,
+		Amount:    dto.Amount,
 		Direction: dto.Direction,
 		Note:      strings.TrimSpace(dto.Note),
 		CreatedBy: dto.CreatedBy,
@@ -164,11 +165,11 @@ func (s *MoneyAccountService) DeleteTransfer(id string) error {
 	return s.accountRepo.DeleteTransfer(id)
 }
 
-func (s *MoneyAccountService) GetAccountBalance(accountID string) (int, error) {
+func (s *MoneyAccountService) GetAccountBalance(accountID string) (decimal.Decimal, error) {
 	return s.accountRepo.GetAccountBalance(accountID)
 }
 
-func (s *MoneyAccountService) GetTotalAllocatedForSpace(spaceID string) (int, error) {
+func (s *MoneyAccountService) GetTotalAllocatedForSpace(spaceID string) (decimal.Decimal, error) {
 	return s.accountRepo.GetTotalAllocatedForSpace(spaceID)
 }
 

internal/service/money_account_test.go

@@ -6,6 +6,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"git.juancwu.dev/juancwu/budgit/internal/testutil"
+	"github.com/shopspring/decimal"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -53,13 +54,13 @@ func TestMoneyAccountService_GetAccountsForSpace(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "acct-svc-list@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Account Svc List Space")
 		account := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Checking", user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account.ID, 5000, model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("50.00"), model.TransferDirectionDeposit, user.ID)
 
 		accounts, err := svc.GetAccountsForSpace(space.ID)
 		require.NoError(t, err)
 		require.Len(t, accounts, 1)
 		assert.Equal(t, "Checking", accounts[0].Name)
-		assert.Equal(t, 5000, accounts[0].BalanceCents)
+		assert.True(t, decimal.RequireFromString("50.00").Equal(accounts[0].Balance))
 	})
 }
 
@@ -74,14 +75,14 @@ func TestMoneyAccountService_CreateTransfer_Deposit(t *testing.T) {
 
 		transfer, err := svc.CreateTransfer(CreateTransferDTO{
 			AccountID: account.ID,
-			Amount:    3000,
+			Amount:    decimal.RequireFromString("30.00"),
 			Direction: model.TransferDirectionDeposit,
 			Note:      "Initial deposit",
 			CreatedBy: user.ID,
-		}, 10000)
+		}, decimal.RequireFromString("100.00"))
 		require.NoError(t, err)
 		assert.NotEmpty(t, transfer.ID)
-		assert.Equal(t, 3000, transfer.AmountCents)
+		assert.True(t, decimal.RequireFromString("30.00").Equal(transfer.Amount))
 		assert.Equal(t, model.TransferDirectionDeposit, transfer.Direction)
 	})
 }
@@ -97,11 +98,11 @@ func TestMoneyAccountService_CreateTransfer_InsufficientBalance(t *testing.T) {
 
 		transfer, err := svc.CreateTransfer(CreateTransferDTO{
 			AccountID: account.ID,
-			Amount:    5000,
+			Amount:    decimal.RequireFromString("50.00"),
 			Direction: model.TransferDirectionDeposit,
 			Note:      "Too much",
 			CreatedBy: user.ID,
-		}, 1000)
+		}, decimal.RequireFromString("10.00"))
 		assert.Error(t, err)
 		assert.Nil(t, transfer)
 	})
@@ -115,18 +116,18 @@ func TestMoneyAccountService_CreateTransfer_Withdrawal(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "acct-svc-withdraw@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Account Svc Withdraw Space")
 		account := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Withdraw Account", user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account.ID, 5000, model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("50.00"), model.TransferDirectionDeposit, user.ID)
 
 		transfer, err := svc.CreateTransfer(CreateTransferDTO{
 			AccountID: account.ID,
-			Amount:    2000,
+			Amount:    decimal.RequireFromString("20.00"),
 			Direction: model.TransferDirectionWithdrawal,
 			Note:      "Withdrawal",
 			CreatedBy: user.ID,
-		}, 0)
+		}, decimal.Zero)
 		require.NoError(t, err)
 		assert.NotEmpty(t, transfer.ID)
-		assert.Equal(t, 2000, transfer.AmountCents)
+		assert.True(t, decimal.RequireFromString("20.00").Equal(transfer.Amount))
 		assert.Equal(t, model.TransferDirectionWithdrawal, transfer.Direction)
 	})
 }
@@ -140,14 +141,14 @@ func TestMoneyAccountService_GetTotalAllocatedForSpace(t *testing.T) {
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Account Svc Total Space")
 
 		account1 := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Account 1", user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account1.ID, 3000, model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account1.ID, decimal.RequireFromString("30.00"), model.TransferDirectionDeposit, user.ID)
 
 		account2 := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "Account 2", user.ID)
-		testutil.CreateTestTransfer(t, dbi.DB, account2.ID, 2000, model.TransferDirectionDeposit, user.ID)
+		testutil.CreateTestTransfer(t, dbi.DB, account2.ID, decimal.RequireFromString("20.00"), model.TransferDirectionDeposit, user.ID)
 
 		total, err := svc.GetTotalAllocatedForSpace(space.ID)
 		require.NoError(t, err)
-		assert.Equal(t, 5000, total)
+		assert.True(t, decimal.RequireFromString("50.00").Equal(total))
 	})
 }
 
@@ -177,7 +178,7 @@ func TestMoneyAccountService_DeleteTransfer(t *testing.T) {
 		user := testutil.CreateTestUser(t, dbi.DB, "acct-svc-deltx@example.com", nil)
 		space := testutil.CreateTestSpace(t, dbi.DB, user.ID, "Account Svc DelTx Space")
 		account := testutil.CreateTestMoneyAccount(t, dbi.DB, space.ID, "DelTx Account", user.ID)
-		transfer := testutil.CreateTestTransfer(t, dbi.DB, account.ID, 1000, model.TransferDirectionDeposit, user.ID)
+		transfer := testutil.CreateTestTransfer(t, dbi.DB, account.ID, decimal.RequireFromString("10.00"), model.TransferDirectionDeposit, user.ID)
 
 		err := svc.DeleteTransfer(transfer.ID)
 		require.NoError(t, err)

internal/service/receipt.go

@@ -7,12 +7,13 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type FundingSourceDTO struct {
 	SourceType model.FundingSourceType
 	AccountID  string
-	Amount     int
+	Amount     decimal.Decimal
 }
 
 type CreateReceiptDTO struct {
@@ -20,7 +21,7 @@ type CreateReceiptDTO struct {
 	SpaceID            string
 	UserID             string
 	Description        string
-	TotalAmount        int
+	TotalAmount        decimal.Decimal
 	Date               time.Time
 	FundingSources     []FundingSourceDTO
 	RecurringReceiptID *string
@@ -31,7 +32,7 @@ type UpdateReceiptDTO struct {
 	SpaceID        string
 	UserID         string
 	Description    string
-	TotalAmount    int
+	TotalAmount    decimal.Decimal
 	Date           time.Time
 	FundingSources []FundingSourceDTO
 }
@@ -57,7 +58,7 @@ func NewReceiptService(
 }
 
 func (s *ReceiptService) CreateReceipt(dto CreateReceiptDTO) (*model.ReceiptWithSources, error) {
-	if dto.TotalAmount <= 0 {
+	if dto.TotalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 	if len(dto.FundingSources) == 0 {
@@ -65,15 +66,15 @@ func (s *ReceiptService) CreateReceipt(dto CreateReceiptDTO) (*model.ReceiptWith
 	}
 
 	// Validate funding sources sum to total
-	var sum int
+	sum := decimal.Zero
 	for _, src := range dto.FundingSources {
-		if src.Amount <= 0 {
+		if src.Amount.LessThanOrEqual(decimal.Zero) {
 			return nil, fmt.Errorf("each funding source amount must be positive")
 		}
-		sum += src.Amount
+		sum = sum.Add(src.Amount)
 	}
-	if sum != dto.TotalAmount {
-		return nil, fmt.Errorf("funding source amounts (%d) must equal total amount (%d)", sum, dto.TotalAmount)
+	if !sum.Equal(dto.TotalAmount) {
+		return nil, fmt.Errorf("funding source amounts (%s) must equal total amount (%s)", sum, dto.TotalAmount)
 	}
 
 	// Validate loan exists and is not paid off
@@ -91,7 +92,7 @@ func (s *ReceiptService) CreateReceipt(dto CreateReceiptDTO) (*model.ReceiptWith
 		LoanID:             dto.LoanID,
 		SpaceID:            dto.SpaceID,
 		Description:        dto.Description,
-		TotalAmountCents:   dto.TotalAmount,
+		TotalAmount:        dto.TotalAmount,
 		Date:               dto.Date,
 		RecurringReceiptID: dto.RecurringReceiptID,
 		CreatedBy:          dto.UserID,
@@ -107,7 +108,7 @@ func (s *ReceiptService) CreateReceipt(dto CreateReceiptDTO) (*model.ReceiptWith
 
 	// Check if loan is now fully paid off
 	totalPaid, err := s.loanRepo.GetTotalPaidForLoan(dto.LoanID)
-	if err == nil && totalPaid >= loan.OriginalAmountCents {
+	if err == nil && totalPaid.GreaterThanOrEqual(loan.OriginalAmount) {
 		_ = s.loanRepo.SetPaidOff(loan.ID, true)
 	}
 
@@ -130,7 +131,7 @@ func (s *ReceiptService) buildLinkedRecords(
 			ID:         uuid.NewString(),
 			ReceiptID:  receipt.ID,
 			SourceType: src.SourceType,
-			AmountCents: src.Amount,
+			Amount:     src.Amount,
 		}
 
 		if src.SourceType == model.FundingSourceBalance {
@@ -139,7 +140,7 @@ func (s *ReceiptService) buildLinkedRecords(
 				SpaceID:     spaceID,
 				CreatedBy:   userID,
 				Description: fmt.Sprintf("Loan payment: %s", description),
-				AmountCents: src.Amount,
+				Amount:      src.Amount,
 				Type:        model.ExpenseTypeExpense,
 				Date:        date,
 				CreatedAt:   now,
@@ -153,7 +154,7 @@ func (s *ReceiptService) buildLinkedRecords(
 			transfer := &model.AccountTransfer{
 				ID:        uuid.NewString(),
 				AccountID: src.AccountID,
-				AmountCents: src.Amount,
+				Amount:    src.Amount,
 				Direction: model.TransferDirectionWithdrawal,
 				Note:      fmt.Sprintf("Loan payment: %s", description),
 				CreatedBy: userID,
@@ -255,7 +256,7 @@ func (s *ReceiptService) DeleteReceipt(id string, spaceID string) error {
 	if err != nil {
 		return nil
 	}
-	if loan.IsPaidOff && totalPaid < loan.OriginalAmountCents {
+	if loan.IsPaidOff && totalPaid.LessThan(loan.OriginalAmount) {
 		_ = s.loanRepo.SetPaidOff(loan.ID, false)
 	}
 
@@ -263,22 +264,22 @@ func (s *ReceiptService) DeleteReceipt(id string, spaceID string) error {
 }
 
 func (s *ReceiptService) UpdateReceipt(dto UpdateReceiptDTO) (*model.ReceiptWithSources, error) {
-	if dto.TotalAmount <= 0 {
+	if dto.TotalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 	if len(dto.FundingSources) == 0 {
 		return nil, fmt.Errorf("at least one funding source is required")
 	}
 
-	var sum int
+	sum := decimal.Zero
 	for _, src := range dto.FundingSources {
-		if src.Amount <= 0 {
+		if src.Amount.LessThanOrEqual(decimal.Zero) {
 			return nil, fmt.Errorf("each funding source amount must be positive")
 		}
-		sum += src.Amount
+		sum = sum.Add(src.Amount)
 	}
-	if sum != dto.TotalAmount {
-		return nil, fmt.Errorf("funding source amounts (%d) must equal total amount (%d)", sum, dto.TotalAmount)
+	if !sum.Equal(dto.TotalAmount) {
+		return nil, fmt.Errorf("funding source amounts (%s) must equal total amount (%s)", sum, dto.TotalAmount)
 	}
 
 	existing, err := s.receiptRepo.GetByID(dto.ID)
@@ -290,7 +291,7 @@ func (s *ReceiptService) UpdateReceipt(dto UpdateReceiptDTO) (*model.ReceiptWith
 	}
 
 	existing.Description = dto.Description
-	existing.TotalAmountCents = dto.TotalAmount
+	existing.TotalAmount = dto.TotalAmount
 	existing.Date = dto.Date
 	existing.UpdatedAt = time.Now()
 
@@ -305,9 +306,9 @@ func (s *ReceiptService) UpdateReceipt(dto UpdateReceiptDTO) (*model.ReceiptWith
 	if err == nil {
 		totalPaid, err := s.loanRepo.GetTotalPaidForLoan(existing.LoanID)
 		if err == nil {
-			if totalPaid >= loan.OriginalAmountCents && !loan.IsPaidOff {
+			if totalPaid.GreaterThanOrEqual(loan.OriginalAmount) && !loan.IsPaidOff {
 				_ = s.loanRepo.SetPaidOff(loan.ID, true)
-			} else if totalPaid < loan.OriginalAmountCents && loan.IsPaidOff {
+			} else if totalPaid.LessThan(loan.OriginalAmount) && loan.IsPaidOff {
 				_ = s.loanRepo.SetPaidOff(loan.ID, false)
 			}
 		}

internal/service/recurring_deposit.go

@@ -9,12 +9,13 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateRecurringDepositDTO struct {
 	SpaceID   string
 	AccountID string
-	Amount    int
+	Amount    decimal.Decimal
 	Frequency model.Frequency
 	StartDate time.Time
 	EndDate   *time.Time
@@ -25,7 +26,7 @@ type CreateRecurringDepositDTO struct {
 type UpdateRecurringDepositDTO struct {
 	ID        string
 	AccountID string
-	Amount    int
+	Amount    decimal.Decimal
 	Frequency model.Frequency
 	StartDate time.Time
 	EndDate   *time.Time
@@ -51,7 +52,7 @@ func NewRecurringDepositService(recurringRepo repository.RecurringDepositReposit
 }
 
 func (s *RecurringDepositService) CreateRecurringDeposit(dto CreateRecurringDepositDTO) (*model.RecurringDeposit, error) {
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -60,7 +61,7 @@ func (s *RecurringDepositService) CreateRecurringDeposit(dto CreateRecurringDepo
 		ID:             uuid.NewString(),
 		SpaceID:        dto.SpaceID,
 		AccountID:      dto.AccountID,
-		AmountCents:    dto.Amount,
+		Amount:         dto.Amount,
 		Frequency:      dto.Frequency,
 		StartDate:      dto.StartDate,
 		EndDate:        dto.EndDate,
@@ -113,7 +114,7 @@ func (s *RecurringDepositService) GetRecurringDepositsWithAccountsForSpace(space
 }
 
 func (s *RecurringDepositService) UpdateRecurringDeposit(dto UpdateRecurringDepositDTO) (*model.RecurringDeposit, error) {
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -123,7 +124,7 @@ func (s *RecurringDepositService) UpdateRecurringDeposit(dto UpdateRecurringDepo
 	}
 
 	existing.AccountID = dto.AccountID
-	existing.AmountCents = dto.Amount
+	existing.Amount = dto.Amount
 	existing.Frequency = dto.Frequency
 	existing.StartDate = dto.StartDate
 	existing.EndDate = dto.EndDate
@@ -221,16 +222,16 @@ func (s *RecurringDepositService) getLocalNow(spaceID, userID string, now time.T
 	return now.In(loc)
 }
 
-func (s *RecurringDepositService) getAvailableBalance(spaceID string) (int, error) {
+func (s *RecurringDepositService) getAvailableBalance(spaceID string) (decimal.Decimal, error) {
 	totalBalance, err := s.expenseService.GetBalanceForSpace(spaceID)
 	if err != nil {
-		return 0, fmt.Errorf("failed to get space balance: %w", err)
+		return decimal.Zero, fmt.Errorf("failed to get space balance: %w", err)
 	}
 	totalAllocated, err := s.accountRepo.GetTotalAllocatedForSpace(spaceID)
 	if err != nil {
-		return 0, fmt.Errorf("failed to get total allocated: %w", err)
+		return decimal.Zero, fmt.Errorf("failed to get total allocated: %w", err)
 	}
-	return totalBalance - totalAllocated, nil
+	return totalBalance.Sub(totalAllocated), nil
 }
 
 func (s *RecurringDepositService) processRecurrence(rd *model.RecurringDeposit, now time.Time) error {
@@ -246,12 +247,12 @@ func (s *RecurringDepositService) processRecurrence(rd *model.RecurringDeposit,
 			return err
 		}
 
-		if availableBalance >= rd.AmountCents {
+		if availableBalance.GreaterThanOrEqual(rd.Amount) {
 			rdID := rd.ID
 			transfer := &model.AccountTransfer{
 				ID:                 uuid.NewString(),
 				AccountID:          rd.AccountID,
-				AmountCents:        rd.AmountCents,
+				Amount:             rd.Amount,
 				Direction:          model.TransferDirectionDeposit,
 				Note:               rd.Title,
 				RecurringDepositID: &rdID,
@@ -265,7 +266,7 @@ func (s *RecurringDepositService) processRecurrence(rd *model.RecurringDeposit,
 			slog.Warn("recurring deposit skipped: insufficient available balance",
 				"recurring_deposit_id", rd.ID,
 				"space_id", rd.SpaceID,
-				"needed", rd.AmountCents,
+				"needed", rd.Amount,
 				"available", availableBalance,
 			)
 		}

internal/service/recurring_expense.go

@@ -8,13 +8,14 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateRecurringExpenseDTO struct {
 	SpaceID         string
 	UserID          string
 	Description     string
-	Amount          int
+	Amount          decimal.Decimal
 	Type            model.ExpenseType
 	PaymentMethodID *string
 	Frequency       model.Frequency
@@ -26,7 +27,7 @@ type CreateRecurringExpenseDTO struct {
 type UpdateRecurringExpenseDTO struct {
 	ID              string
 	Description     string
-	Amount          int
+	Amount          decimal.Decimal
 	Type            model.ExpenseType
 	PaymentMethodID *string
 	Frequency       model.Frequency
@@ -55,7 +56,7 @@ func (s *RecurringExpenseService) CreateRecurringExpense(dto CreateRecurringExpe
 	if dto.Description == "" {
 		return nil, fmt.Errorf("description cannot be empty")
 	}
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -65,7 +66,7 @@ func (s *RecurringExpenseService) CreateRecurringExpense(dto CreateRecurringExpe
 		SpaceID:         dto.SpaceID,
 		CreatedBy:       dto.UserID,
 		Description:     dto.Description,
-		AmountCents:     dto.Amount,
+		Amount:          dto.Amount,
 		Type:            dto.Type,
 		PaymentMethodID: dto.PaymentMethodID,
 		Frequency:       dto.Frequency,
@@ -127,7 +128,7 @@ func (s *RecurringExpenseService) UpdateRecurringExpense(dto UpdateRecurringExpe
 	if dto.Description == "" {
 		return nil, fmt.Errorf("description cannot be empty")
 	}
-	if dto.Amount <= 0 {
+	if dto.Amount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -137,7 +138,7 @@ func (s *RecurringExpenseService) UpdateRecurringExpense(dto UpdateRecurringExpe
 	}
 
 	existing.Description = dto.Description
-	existing.AmountCents = dto.Amount
+	existing.Amount = dto.Amount
 	existing.Type = dto.Type
 	existing.PaymentMethodID = dto.PaymentMethodID
 	existing.Frequency = dto.Frequency
@@ -229,7 +230,7 @@ func (s *RecurringExpenseService) processRecurrence(re *model.RecurringExpense,
 			SpaceID:            re.SpaceID,
 			CreatedBy:          re.CreatedBy,
 			Description:        re.Description,
-			AmountCents:        re.AmountCents,
+			Amount:             re.Amount,
 			Type:               re.Type,
 			Date:               re.NextOccurrence,
 			PaymentMethodID:    re.PaymentMethodID,

internal/service/recurring_receipt.go

@@ -8,6 +8,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/repository"
 	"github.com/google/uuid"
+	"github.com/shopspring/decimal"
 )
 
 type CreateRecurringReceiptDTO struct {
@@ -15,7 +16,7 @@ type CreateRecurringReceiptDTO struct {
 	SpaceID        string
 	UserID         string
 	Description    string
-	TotalAmount    int
+	TotalAmount    decimal.Decimal
 	Frequency      model.Frequency
 	StartDate      time.Time
 	EndDate        *time.Time
@@ -25,7 +26,7 @@ type CreateRecurringReceiptDTO struct {
 type UpdateRecurringReceiptDTO struct {
 	ID             string
 	Description    string
-	TotalAmount    int
+	TotalAmount    decimal.Decimal
 	Frequency      model.Frequency
 	StartDate      time.Time
 	EndDate        *time.Time
@@ -57,18 +58,18 @@ func NewRecurringReceiptService(
 }
 
 func (s *RecurringReceiptService) CreateRecurringReceipt(dto CreateRecurringReceiptDTO) (*model.RecurringReceiptWithSources, error) {
-	if dto.TotalAmount <= 0 {
+	if dto.TotalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 	if len(dto.FundingSources) == 0 {
 		return nil, fmt.Errorf("at least one funding source is required")
 	}
 
-	var sum int
+	sum := decimal.Zero
 	for _, src := range dto.FundingSources {
-		sum += src.Amount
+		sum = sum.Add(src.Amount)
 	}
-	if sum != dto.TotalAmount {
+	if !sum.Equal(dto.TotalAmount) {
 		return nil, fmt.Errorf("funding source amounts must equal total amount")
 	}
 
@@ -78,7 +79,7 @@ func (s *RecurringReceiptService) CreateRecurringReceipt(dto CreateRecurringRece
 		LoanID:         dto.LoanID,
 		SpaceID:        dto.SpaceID,
 		Description:    dto.Description,
-		TotalAmountCents: dto.TotalAmount,
+		TotalAmount:    dto.TotalAmount,
 		Frequency:      dto.Frequency,
 		StartDate:      dto.StartDate,
 		EndDate:        dto.EndDate,
@@ -95,7 +96,7 @@ func (s *RecurringReceiptService) CreateRecurringReceipt(dto CreateRecurringRece
 			ID:                 uuid.NewString(),
 			RecurringReceiptID: rr.ID,
 			SourceType:         src.SourceType,
-			AmountCents:        src.Amount,
+			Amount:             src.Amount,
 		}
 		if src.SourceType == model.FundingSourceAccount {
 			acctID := src.AccountID
@@ -142,7 +143,7 @@ func (s *RecurringReceiptService) GetRecurringReceiptsWithSourcesForLoan(loanID
 }
 
 func (s *RecurringReceiptService) UpdateRecurringReceipt(dto UpdateRecurringReceiptDTO) (*model.RecurringReceipt, error) {
-	if dto.TotalAmount <= 0 {
+	if dto.TotalAmount.LessThanOrEqual(decimal.Zero) {
 		return nil, fmt.Errorf("amount must be positive")
 	}
 
@@ -152,7 +153,7 @@ func (s *RecurringReceiptService) UpdateRecurringReceipt(dto UpdateRecurringRece
 	}
 
 	existing.Description = dto.Description
-	existing.TotalAmountCents = dto.TotalAmount
+	existing.TotalAmount = dto.TotalAmount
 	existing.Frequency = dto.Frequency
 	existing.StartDate = dto.StartDate
 	existing.EndDate = dto.EndDate
@@ -168,7 +169,7 @@ func (s *RecurringReceiptService) UpdateRecurringReceipt(dto UpdateRecurringRece
 			ID:                 uuid.NewString(),
 			RecurringReceiptID: existing.ID,
 			SourceType:         src.SourceType,
-			AmountCents:        src.Amount,
+			Amount:             src.Amount,
 		}
 		if src.SourceType == model.FundingSourceAccount {
 			acctID := src.AccountID
@@ -262,7 +263,7 @@ func (s *RecurringReceiptService) processRecurrence(rr *model.RecurringReceipt,
 			fundingSources[i] = FundingSourceDTO{
 				SourceType: src.SourceType,
 				AccountID:  accountID,
-				Amount:     src.AmountCents,
+				Amount:     src.Amount,
 			}
 		}
 
@@ -272,7 +273,7 @@ func (s *RecurringReceiptService) processRecurrence(rr *model.RecurringReceipt,
 			SpaceID:            rr.SpaceID,
 			UserID:             rr.CreatedBy,
 			Description:        rr.Description,
-			TotalAmount:        rr.TotalAmountCents,
+			TotalAmount:        rr.TotalAmount,
 			Date:               rr.NextOccurrence,
 			FundingSources:     fundingSources,
 			RecurringReceiptID: &rrID,

internal/service/report.go

@@ -73,7 +73,7 @@ func (s *ReportService) GetSpendingReport(spaceID string, from, to time.Time) (*
 		TopExpenses:     topWithTags,
 		TotalIncome:     totalIncome,
 		TotalExpenses:   totalExpenses,
-		NetBalance:      totalIncome - totalExpenses,
+		NetBalance:      totalIncome.Sub(totalExpenses),
 	}, nil
 }
 

internal/testutil/seed.go

@@ -7,6 +7,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"github.com/google/uuid"
 	"github.com/jmoiron/sqlx"
+	"github.com/shopspring/decimal"
 )
 
 // CreateTestUser inserts a user directly into the database.
@@ -152,7 +153,7 @@ func CreateTestListItem(t *testing.T, db *sqlx.DB, listID, name, createdBy strin
 }
 
 // CreateTestExpense inserts an expense directly into the database.
-func CreateTestExpense(t *testing.T, db *sqlx.DB, spaceID, userID, desc string, amount int, typ model.ExpenseType) *model.Expense {
+func CreateTestExpense(t *testing.T, db *sqlx.DB, spaceID, userID, desc string, amount decimal.Decimal, typ model.ExpenseType) *model.Expense {
 	t.Helper()
 	now := time.Now()
 	expense := &model.Expense{
@@ -160,15 +161,15 @@ func CreateTestExpense(t *testing.T, db *sqlx.DB, spaceID, userID, desc string,
 		SpaceID:     spaceID,
 		CreatedBy:   userID,
 		Description: desc,
-		AmountCents: amount,
+		Amount:      amount,
 		Type:        typ,
 		Date:        now,
 		CreatedAt:   now,
 		UpdatedAt:   now,
 	}
 	_, err := db.Exec(
-		`INSERT INTO expenses (id, space_id, created_by, description, amount_cents, type, date, payment_method_id, created_at, updated_at) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)`,
-		expense.ID, expense.SpaceID, expense.CreatedBy, expense.Description, expense.AmountCents,
+		`INSERT INTO expenses (id, space_id, created_by, description, amount, type, date, payment_method_id, created_at, updated_at, amount_cents) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, 0)`,
+		expense.ID, expense.SpaceID, expense.CreatedBy, expense.Description, expense.Amount,
 		expense.Type, expense.Date, expense.PaymentMethodID, expense.CreatedAt, expense.UpdatedAt,
 	)
 	if err != nil {
@@ -200,20 +201,20 @@ func CreateTestMoneyAccount(t *testing.T, db *sqlx.DB, spaceID, name, createdBy
 }
 
 // CreateTestTransfer inserts an account transfer directly into the database.
-func CreateTestTransfer(t *testing.T, db *sqlx.DB, accountID string, amount int, direction model.TransferDirection, createdBy string) *model.AccountTransfer {
+func CreateTestTransfer(t *testing.T, db *sqlx.DB, accountID string, amount decimal.Decimal, direction model.TransferDirection, createdBy string) *model.AccountTransfer {
 	t.Helper()
 	transfer := &model.AccountTransfer{
 		ID:        uuid.NewString(),
 		AccountID: accountID,
-		AmountCents: amount,
+		Amount:    amount,
 		Direction: direction,
 		Note:      "test transfer",
 		CreatedBy: createdBy,
 		CreatedAt: time.Now(),
 	}
 	_, err := db.Exec(
-		`INSERT INTO account_transfers (id, account_id, amount_cents, direction, note, created_by, created_at) VALUES ($1, $2, $3, $4, $5, $6, $7)`,
-		transfer.ID, transfer.AccountID, transfer.AmountCents, transfer.Direction, transfer.Note, transfer.CreatedBy, transfer.CreatedAt,
+		`INSERT INTO account_transfers (id, account_id, amount, direction, note, created_by, created_at, amount_cents) VALUES ($1, $2, $3, $4, $5, $6, $7, 0)`,
+		transfer.ID, transfer.AccountID, transfer.Amount, transfer.Direction, transfer.Note, transfer.CreatedBy, transfer.CreatedAt,
 	)
 	if err != nil {
 		t.Fatalf("CreateTestTransfer: %v", err)

internal/ui/components/expense/expense.templ

@@ -14,6 +14,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/paymentmethod"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/radio"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/tagcombobox"
+	"github.com/shopspring/decimal"
 )
 
 type AddExpenseFormProps struct {
@@ -215,7 +216,7 @@ templ EditExpenseForm(spaceID string, exp *model.ExpenseWithTagsAndMethod, metho
 				Name:       "amount",
 				ID:         "edit-amount-" + exp.ID,
 				Type:       "number",
-				Value:      fmt.Sprintf("%.2f", float64(exp.AmountCents)/100.0),
+				Value:      model.FormatDecimal(exp.Amount),
 				Attributes: templ.Attributes{"step": "0.01", "required": "true"},
 			})
 		</div>
@@ -345,7 +346,7 @@ templ ItemSelectorSection(listsWithItems []model.ListWithUncheckedItems, oob boo
 	</div>
 }
 
-templ BalanceCard(spaceID string, balance int, allocated int, oob bool) {
+templ BalanceCard(spaceID string, balance decimal.Decimal, allocated decimal.Decimal, oob bool) {
 	<div
 		id="balance-card"
 		class="border rounded-lg p-4 bg-card text-card-foreground"
@@ -354,11 +355,11 @@ templ BalanceCard(spaceID string, balance int, allocated int, oob bool) {
 		}
 	>
 		<h2 class="text-lg font-semibold">Current Balance</h2>
-		<p class={ "text-3xl font-bold", templ.KV("text-destructive", balance < 0) }>
-			{ fmt.Sprintf("$%.2f", float64(balance)/100.0) }
-			if allocated > 0 {
+		<p class={ "text-3xl font-bold", templ.KV("text-destructive", balance.LessThan(decimal.Zero)) }>
+			{ model.FormatMoney(balance) }
+			if allocated.GreaterThan(decimal.Zero) {
 				<span class="text-base font-normal text-muted-foreground">
-					({ fmt.Sprintf("$%.2f", float64(allocated)/100.0) } in accounts)
+					({ model.FormatMoney(allocated) } in accounts)
 				</span>
 			}
 		</p>

internal/ui/components/moneyaccount/moneyaccount.templ

@@ -13,6 +13,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/label"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/pagination"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/selectbox"
+	"github.com/shopspring/decimal"
 )
 
 func frequencyLabel(f model.Frequency) string {
@@ -32,7 +33,7 @@ func frequencyLabel(f model.Frequency) string {
 	}
 }
 
-templ BalanceSummaryCard(spaceID string, totalBalance int, availableBalance int, oob bool) {
+templ BalanceSummaryCard(spaceID string, totalBalance decimal.Decimal, availableBalance decimal.Decimal, oob bool) {
 	<div
 		id="accounts-balance-summary"
 		class="border rounded-lg p-4 bg-card text-card-foreground"
@@ -44,20 +45,20 @@ templ BalanceSummaryCard(spaceID string, totalBalance int, availableBalance int,
 		<div class="grid grid-cols-3 gap-4">
 			<div>
 				<p class="text-sm text-muted-foreground">Total Balance</p>
-				<p class={ "text-xl font-bold", templ.KV("text-destructive", totalBalance < 0) }>
-					{ fmt.Sprintf("$%.2f", float64(totalBalance)/100.0) }
+				<p class={ "text-xl font-bold", templ.KV("text-destructive", totalBalance.LessThan(decimal.Zero)) }>
+					{ model.FormatMoney(totalBalance) }
 				</p>
 			</div>
 			<div>
 				<p class="text-sm text-muted-foreground">Allocated</p>
 				<p class="text-xl font-bold">
-					{ fmt.Sprintf("$%.2f", float64(totalBalance-availableBalance)/100.0) }
+					{ model.FormatMoney(totalBalance.Sub(availableBalance)) }
 				</p>
 			</div>
 			<div>
 				<p class="text-sm text-muted-foreground">Available</p>
-				<p class={ "text-xl font-bold", templ.KV("text-destructive", availableBalance < 0) }>
-					{ fmt.Sprintf("$%.2f", float64(availableBalance)/100.0) }
+				<p class={ "text-xl font-bold", templ.KV("text-destructive", availableBalance.LessThan(decimal.Zero)) }>
+					{ model.FormatMoney(availableBalance) }
 				</p>
 			</div>
 		</div>
@@ -79,8 +80,8 @@ templ AccountCard(spaceID string, acct *model.MoneyAccountWithBalance, oob ...bo
 		<div class="flex justify-between items-start mb-3">
 			<div>
 				<h3 class="font-semibold text-lg">{ acct.Name }</h3>
-				<p class={ "text-2xl font-bold", templ.KV("text-destructive", acct.BalanceCents < 0) }>
-					{ fmt.Sprintf("$%.2f", float64(acct.BalanceCents)/100.0) }
+				<p class={ "text-2xl font-bold", templ.KV("text-destructive", acct.Balance.LessThan(decimal.Zero)) }>
+					{ model.FormatMoney(acct.Balance) }
 				</p>
 			</div>
 			<div class="flex gap-1">
@@ -356,7 +357,7 @@ templ RecurringDepositItem(spaceID string, rd *model.RecurringDepositWithAccount
 		</div>
 		<div class="flex items-center gap-2">
 			<span class="font-bold text-green-600 whitespace-nowrap">
-				+{ fmt.Sprintf("$%.2f", float64(rd.AmountCents)/100.0) }
+				+{ model.FormatMoney(rd.Amount) }
 			</span>
 			// Toggle
 			@button.Button(button.Props{
@@ -636,11 +637,11 @@ templ TransferHistoryItem(spaceID string, t *model.AccountTransferWithAccount) {
 		<div class="flex items-center gap-2">
 			if t.Direction == model.TransferDirectionDeposit {
 				<span class="font-bold text-green-600 whitespace-nowrap">
-					+{ fmt.Sprintf("$%.2f", float64(t.AmountCents)/100.0) }
+					+{ model.FormatMoney(t.Amount) }
 				</span>
 			} else {
 				<span class="font-bold text-destructive whitespace-nowrap">
-					-{ fmt.Sprintf("$%.2f", float64(t.AmountCents)/100.0) }
+					-{ model.FormatMoney(t.Amount) }
 				</span>
 			}
 			@button.Button(button.Props{
@@ -696,7 +697,7 @@ templ EditRecurringDepositForm(spaceID string, rd *model.RecurringDepositWithAcc
 				Name:       "amount",
 				ID:         "edit-rd-amount-" + rd.ID,
 				Type:       "number",
-				Value:      fmt.Sprintf("%.2f", float64(rd.AmountCents)/100.0),
+				Value:      model.FormatDecimal(rd.Amount),
 				Attributes: templ.Attributes{"step": "0.01", "required": "true", "min": "0.01"},
 			})
 		</div>

internal/ui/components/recurring/recurring.templ

@@ -73,11 +73,11 @@ templ RecurringItem(spaceID string, re *model.RecurringExpenseWithTagsAndMethod,
 		<div class="flex items-center gap-1 shrink-0">
 			if re.Type == model.ExpenseTypeExpense {
 				<p class="font-bold text-destructive">
-					- { fmt.Sprintf("$%.2f", float64(re.AmountCents)/100.0) }
+					- { model.FormatMoney(re.Amount) }
 				</p>
 			} else {
 				<p class="font-bold text-green-500">
-					+ { fmt.Sprintf("$%.2f", float64(re.AmountCents)/100.0) }
+					+ { model.FormatMoney(re.Amount) }
 				</p>
 			}
 			// Toggle pause/resume
@@ -352,7 +352,7 @@ templ EditRecurringForm(spaceID string, re *model.RecurringExpenseWithTagsAndMet
 				Name:       "amount",
 				ID:         "edit-recurring-amount-" + re.ID,
 				Type:       "number",
-				Value:      fmt.Sprintf("%.2f", float64(re.AmountCents)/100.0),
+				Value:      model.FormatDecimal(re.Amount),
 				Attributes: templ.Attributes{"step": "0.01", "required": "true"},
 			})
 		</div>

internal/ui/pages/app_space_accounts.templ

@@ -6,9 +6,10 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/dialog"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/moneyaccount"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/layouts"
+	"github.com/shopspring/decimal"
 )
 
-templ SpaceAccountsPage(space *model.Space, accounts []model.MoneyAccountWithBalance, totalBalance int, availableBalance int, transfers []*model.AccountTransferWithAccount, currentPage, totalPages int) {
+templ SpaceAccountsPage(space *model.Space, accounts []model.MoneyAccountWithBalance, totalBalance decimal.Decimal, availableBalance decimal.Decimal, transfers []*model.AccountTransferWithAccount, currentPage, totalPages int) {
 	@layouts.Space("Accounts", space) {
 		<div class="space-y-4">
 			<div class="flex justify-between items-center">

internal/ui/pages/app_space_budgets.templ

@@ -159,14 +159,14 @@ templ BudgetCard(spaceID string, b *model.BudgetWithSpent, tags []*model.Tag) {
 		// Progress bar
 		<div class="space-y-1">
 			<div class="flex justify-between text-sm">
-				<span>{ fmt.Sprintf("$%.2f", float64(b.SpentCents)/100.0) } spent</span>
-				<span>of { fmt.Sprintf("$%.2f", float64(b.AmountCents)/100.0) }</span>
+				<span>{ model.FormatMoney(b.Spent) } spent</span>
+				<span>of { model.FormatMoney(b.Amount) }</span>
 			</div>
 			<div class="w-full bg-muted rounded-full h-2.5">
 				<div class={ "h-2.5 rounded-full transition-all", progressBarColor(b.Status) } style={ fmt.Sprintf("width: %.1f%%", pct) }></div>
 			</div>
 			if b.Status == model.BudgetStatusOver {
-				<p class="text-xs text-destructive font-medium">Over budget by { fmt.Sprintf("$%.2f", float64(b.SpentCents-b.AmountCents)/100.0) }</p>
+				<p class="text-xs text-destructive font-medium">Over budget by { model.FormatMoney(b.Spent.Sub(b.Amount)) }</p>
 			}
 		</div>
 	</div>
@@ -311,7 +311,7 @@ templ EditBudgetForm(spaceID string, b *model.BudgetWithSpent, tags []*model.Tag
 				Name:       "amount",
 				ID:         "edit-budget-amount-" + b.ID,
 				Type:       "number",
-				Value:      fmt.Sprintf("%.2f", float64(b.AmountCents)/100.0),
+				Value:      model.FormatDecimal(b.Amount),
 				Attributes: templ.Attributes{"step": "0.01", "required": "true"},
 			})
 		</div>

internal/ui/pages/app_space_expenses.templ

@@ -3,6 +3,7 @@ package pages
 import (
 	"fmt"
 	"strconv"
+	"github.com/shopspring/decimal"
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/badge"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
@@ -14,7 +15,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/blocks/dialogs"
 )
 
-templ SpaceExpensesPage(space *model.Space, expenses []*model.ExpenseWithTagsAndMethod, balance int, allocated int, tags []*model.Tag, listsWithItems []model.ListWithUncheckedItems, methods []*model.PaymentMethod, currentPage, totalPages int) {
+templ SpaceExpensesPage(space *model.Space, expenses []*model.ExpenseWithTagsAndMethod, balance decimal.Decimal, allocated decimal.Decimal, tags []*model.Tag, listsWithItems []model.ListWithUncheckedItems, methods []*model.PaymentMethod, currentPage, totalPages int) {
 	@layouts.Space("Expenses", space) {
 		<div class="space-y-4">
 			<div class="flex justify-between items-center">
@@ -121,11 +122,11 @@ templ ExpenseListItem(spaceID string, exp *model.ExpenseWithTagsAndMethod, metho
 		<div class="flex items-center gap-1 shrink-0">
 			if exp.Type == model.ExpenseTypeExpense {
 				<p class="font-bold text-destructive">
-					- { fmt.Sprintf("$%.2f", float64(exp.AmountCents)/100.0) }
+					- { model.FormatMoney(exp.Amount) }
 				</p>
 			} else {
 				<p class="font-bold text-green-500">
-					+ { fmt.Sprintf("$%.2f", float64(exp.AmountCents)/100.0) }
+					+ { model.FormatMoney(exp.Amount) }
 				</p>
 			}
 			// Edit button
@@ -186,12 +187,12 @@ templ ExpenseListItem(spaceID string, exp *model.ExpenseWithTagsAndMethod, metho
 	</div>
 }
 
-templ ExpenseCreatedResponse(spaceID string, expenses []*model.ExpenseWithTagsAndMethod, balance int, allocated int, tags []*model.Tag, currentPage, totalPages int) {
+templ ExpenseCreatedResponse(spaceID string, expenses []*model.ExpenseWithTagsAndMethod, balance decimal.Decimal, allocated decimal.Decimal, tags []*model.Tag, currentPage, totalPages int) {
 	@ExpensesListContent(spaceID, expenses, nil, tags, currentPage, totalPages)
 	@expense.BalanceCard(spaceID, balance, allocated, true)
 }
 
-templ ExpenseUpdatedResponse(spaceID string, exp *model.ExpenseWithTagsAndMethod, balance int, allocated int, methods []*model.PaymentMethod, tags []*model.Tag) {
+templ ExpenseUpdatedResponse(spaceID string, exp *model.ExpenseWithTagsAndMethod, balance decimal.Decimal, allocated decimal.Decimal, methods []*model.PaymentMethod, tags []*model.Tag) {
 	@ExpenseListItem(spaceID, exp, methods, tags)
 	@expense.BalanceCard(exp.SpaceID, balance, allocated, true)
 }

internal/ui/pages/app_space_loan_detail.templ

@@ -3,6 +3,7 @@ package pages
 import (
 	"fmt"
 	"strconv"
+	"github.com/shopspring/decimal"
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/badge"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
@@ -17,7 +18,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/layouts"
 )
 
-templ SpaceLoanDetailPage(space *model.Space, loan *model.LoanWithPaymentSummary, receipts []*model.ReceiptWithSourcesAndAccounts, currentPage, totalPages int, recurringReceipts []*model.RecurringReceiptWithSources, accounts []model.MoneyAccountWithBalance, availableBalance int) {
+templ SpaceLoanDetailPage(space *model.Space, loan *model.LoanWithPaymentSummary, receipts []*model.ReceiptWithSourcesAndAccounts, currentPage, totalPages int, recurringReceipts []*model.RecurringReceiptWithSources, accounts []model.MoneyAccountWithBalance, availableBalance decimal.Decimal) {
 	@layouts.Space(loan.Name, space) {
 		<div class="space-y-6">
 			// Loan Summary Card
@@ -94,8 +95,8 @@ templ SpaceLoanDetailPage(space *model.Space, loan *model.LoanWithPaymentSummary
 
 templ LoanSummaryCard(spaceID string, loan *model.LoanWithPaymentSummary) {
 	{{ progressPct := 0 }}
-	if loan.OriginalAmountCents > 0 {
-		{{ progressPct = (loan.TotalPaidCents * 100) / loan.OriginalAmountCents }}
+	if !loan.OriginalAmount.IsZero() {
+		{{ progressPct = int(loan.TotalPaid.Div(loan.OriginalAmount).Mul(decimal.NewFromInt(100)).IntPart()) }}
 		if progressPct > 100 {
 			{{ progressPct = 100 }}
 		}
@@ -154,17 +155,17 @@ templ LoanSummaryCard(spaceID string, loan *model.LoanWithPaymentSummary) {
 				<div class="grid grid-cols-3 gap-4 text-center">
 					<div>
 						<p class="text-sm text-muted-foreground">Original</p>
-						<p class="text-lg font-semibold">{ fmt.Sprintf("$%.2f", float64(loan.OriginalAmountCents)/100.0) }</p>
+						<p class="text-lg font-semibold">{ model.FormatMoney(loan.OriginalAmount) }</p>
 					</div>
 					<div>
 						<p class="text-sm text-muted-foreground">Paid</p>
-						<p class="text-lg font-semibold text-green-600">{ fmt.Sprintf("$%.2f", float64(loan.TotalPaidCents)/100.0) }</p>
+						<p class="text-lg font-semibold text-green-600">{ model.FormatMoney(loan.TotalPaid) }</p>
 					</div>
 					<div>
 						<p class="text-sm text-muted-foreground">Remaining</p>
 						<p class="text-lg font-semibold">
-							if loan.RemainingCents > 0 {
-								{ fmt.Sprintf("$%.2f", float64(loan.RemainingCents)/100.0) }
+							if loan.Remaining.GreaterThan(decimal.Zero) {
+								{ model.FormatMoney(loan.Remaining) }
 							} else {
 								$0.00
 							}
@@ -244,7 +245,7 @@ templ ReceiptListItem(spaceID, loanID string, receipt *model.ReceiptWithSourcesA
 	<div id={ "receipt-" + receipt.ID } class="p-4 flex justify-between items-start">
 		<div class="space-y-1">
 			<div class="flex items-center gap-2">
-				<span class="font-medium">{ fmt.Sprintf("$%.2f", float64(receipt.TotalAmountCents)/100.0) }</span>
+				<span class="font-medium">{ model.FormatMoney(receipt.TotalAmount) }</span>
 				<span class="text-sm text-muted-foreground">{ receipt.Date.Format("Jan 2, 2006") }</span>
 				if receipt.RecurringReceiptID != nil {
 					@icon.Repeat(icon.Props{Class: "size-3 text-muted-foreground"})
@@ -257,11 +258,11 @@ templ ReceiptListItem(spaceID, loanID string, receipt *model.ReceiptWithSourcesA
 				for _, src := range receipt.Sources {
 					if src.SourceType == "balance" {
 						@badge.Badge(badge.Props{Variant: badge.VariantSecondary, Class: "text-xs"}) {
-							{ fmt.Sprintf("Balance $%.2f", float64(src.AmountCents)/100.0) }
+							{ fmt.Sprintf("Balance %s", model.FormatMoney(src.Amount)) }
 						}
 					} else {
 						@badge.Badge(badge.Props{Variant: badge.VariantOutline, Class: "text-xs"}) {
-							{ fmt.Sprintf("%s $%.2f", src.AccountName, float64(src.AmountCents)/100.0) }
+							{ fmt.Sprintf("%s %s", src.AccountName, model.FormatMoney(src.Amount)) }
 						}
 					}
 				}
@@ -304,7 +305,7 @@ templ RecurringReceiptItem(spaceID, loanID string, rr *model.RecurringReceiptWit
 		<div class="space-y-1">
 			<div class="flex items-center gap-2">
 				@icon.Repeat(icon.Props{Class: "size-4"})
-				<span class="font-medium">{ fmt.Sprintf("$%.2f", float64(rr.TotalAmountCents)/100.0) }</span>
+				<span class="font-medium">{ model.FormatMoney(rr.TotalAmount) }</span>
 				<span class="text-sm text-muted-foreground">{ string(rr.Frequency) }</span>
 				if !rr.IsActive {
 					@badge.Badge(badge.Props{Variant: badge.VariantSecondary}) {
@@ -322,12 +323,12 @@ templ RecurringReceiptItem(spaceID, loanID string, rr *model.RecurringReceiptWit
 				for _, src := range rr.Sources {
 					if src.SourceType == "balance" {
 						@badge.Badge(badge.Props{Variant: badge.VariantSecondary, Class: "text-xs"}) {
-							{ fmt.Sprintf("Balance $%.2f", float64(src.AmountCents)/100.0) }
+							{ fmt.Sprintf("Balance %s", model.FormatMoney(src.Amount)) }
 						}
 					} else {
 						@badge.Badge(badge.Props{Variant: badge.VariantOutline, Class: "text-xs"}) {
 							if src.AccountID != nil {
-								{ fmt.Sprintf("Account $%.2f", float64(src.AmountCents)/100.0) }
+								{ fmt.Sprintf("Account %s", model.FormatMoney(src.Amount)) }
 							}
 						}
 					}
@@ -379,7 +380,7 @@ templ RecurringReceiptItem(spaceID, loanID string, rr *model.RecurringReceiptWit
 	</div>
 }
 
-templ CreateReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWithBalance, availableBalance int) {
+templ CreateReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWithBalance, availableBalance decimal.Decimal) {
 	<form
 		hx-post={ fmt.Sprintf("/app/spaces/%s/loans/%s/receipts", spaceID, loanID) }
 		hx-swap="none"
@@ -423,7 +424,7 @@ templ CreateReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWit
 		<div class="space-y-2">
 			<label class="text-sm font-medium">Funding Sources</label>
 			<p class="text-xs text-muted-foreground">
-				Available balance: { fmt.Sprintf("$%.2f", float64(availableBalance)/100.0) }
+				Available balance: { model.FormatMoney(availableBalance) }
 			</p>
 			<div id="funding-sources" class="space-y-2">
 				<div class="flex gap-2 items-center source-row">
@@ -431,7 +432,7 @@ templ CreateReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWit
 						<option value="balance">General Balance</option>
 						for _, acct := range accounts {
 							<option value="account" data-account-id={ acct.ID }>
-								{ acct.Name } ({ fmt.Sprintf("$%.2f", float64(acct.BalanceCents)/100.0) })
+								{ acct.Name } ({ model.FormatMoney(acct.Balance) })
 							</option>
 						}
 					</select>
@@ -483,7 +484,7 @@ templ CreateReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWit
 	</script>
 }
 
-templ CreateRecurringReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWithBalance, availableBalance int) {
+templ CreateRecurringReceiptForm(spaceID, loanID string, accounts []model.MoneyAccountWithBalance, availableBalance decimal.Decimal) {
 	<form
 		hx-post={ fmt.Sprintf("/app/spaces/%s/loans/%s/recurring", spaceID, loanID) }
 		hx-swap="none"
@@ -547,7 +548,7 @@ templ CreateRecurringReceiptForm(spaceID, loanID string, accounts []model.MoneyA
 		<div class="space-y-2">
 			<label class="text-sm font-medium">Funding Sources</label>
 			<p class="text-xs text-muted-foreground">
-				Current balance: { fmt.Sprintf("$%.2f", float64(availableBalance)/100.0) }
+				Current balance: { model.FormatMoney(availableBalance) }
 			</p>
 			<div id="recurring-funding-sources" class="space-y-2">
 				<div class="flex gap-2 items-center recurring-source-row">
@@ -555,7 +556,7 @@ templ CreateRecurringReceiptForm(spaceID, loanID string, accounts []model.MoneyA
 						<option value="balance">General Balance</option>
 						for _, acct := range accounts {
 							<option value="account" data-account-id={ acct.ID }>
-								{ acct.Name } ({ fmt.Sprintf("$%.2f", float64(acct.BalanceCents)/100.0) })
+								{ acct.Name } ({ model.FormatMoney(acct.Balance) })
 							</option>
 						}
 					</select>

internal/ui/pages/app_space_loans.templ

@@ -3,6 +3,7 @@ package pages
 import (
 	"fmt"
 	"strconv"
+	"github.com/shopspring/decimal"
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/card"
@@ -185,8 +186,8 @@ templ LoansListContent(spaceID string, loans []*model.LoanWithPaymentSummary, cu
 
 templ LoanCard(spaceID string, loan *model.LoanWithPaymentSummary) {
 	{{ progressPct := 0 }}
-	if loan.OriginalAmountCents > 0 {
-		{{ progressPct = (loan.TotalPaidCents * 100) / loan.OriginalAmountCents }}
+	if !loan.OriginalAmount.IsZero() {
+		{{ progressPct = int(loan.TotalPaid.Div(loan.OriginalAmount).Mul(decimal.NewFromInt(100)).IntPart()) }}
 		if progressPct > 100 {
 			{{ progressPct = 100 }}
 		}
@@ -205,7 +206,7 @@ templ LoanCard(spaceID string, loan *model.LoanWithPaymentSummary) {
 					}
 				</div>
 				@card.Description() {
-					{ fmt.Sprintf("$%.2f", float64(loan.OriginalAmountCents)/100.0) }
+					{ model.FormatMoney(loan.OriginalAmount) }
 					if loan.InterestRateBps > 0 {
 						{ fmt.Sprintf(" @ %.2f%%", float64(loan.InterestRateBps)/100.0) }
 					}
@@ -218,9 +219,9 @@ templ LoanCard(spaceID string, loan *model.LoanWithPaymentSummary) {
 					Class: "h-2",
 				})
 				<div class="flex justify-between text-sm text-muted-foreground mt-2">
-					<span>Paid: { fmt.Sprintf("$%.2f", float64(loan.TotalPaidCents)/100.0) }</span>
-					if loan.RemainingCents > 0 {
-						<span>Left: { fmt.Sprintf("$%.2f", float64(loan.RemainingCents)/100.0) }</span>
+					<span>Paid: { model.FormatMoney(loan.TotalPaid) }</span>
+					if loan.Remaining.GreaterThan(decimal.Zero) {
+						<span>Left: { model.FormatMoney(loan.Remaining) }</span>
 					} else {
 						<span class="text-green-600">Fully paid</span>
 					}

internal/ui/pages/app_space_overview.templ

@@ -3,6 +3,7 @@ package pages
 import (
 	"fmt"
 	"sort"
+	"github.com/shopspring/decimal"
 	"git.juancwu.dev/juancwu/budgit/internal/model"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/badge"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
@@ -14,8 +15,8 @@ import (
 
 type OverviewData struct {
 	Space             *model.Space
-	Balance           int
-	Allocated         int
+	Balance           decimal.Decimal
+	Allocated         decimal.Decimal
 	Report            *model.SpendingReport
 	Budgets           []*model.BudgetWithSpent
 	UpcomingRecurring []*model.RecurringExpenseWithTagsAndMethod
@@ -143,12 +144,12 @@ templ overviewBalanceCard(data OverviewData) {
 			<h3 class="font-semibold mb-3">Current Balance</h3>
 			@dialogs.AddTransaction(data.Space, data.Tags, data.ListsWithItems, data.Methods)
 		</div>
-		<p class={ "text-3xl font-bold", templ.KV("text-destructive", data.Balance < 0) }>
-			{ fmt.Sprintf("$%.2f", float64(data.Balance)/100.0) }
+		<p class={ "text-3xl font-bold", templ.KV("text-destructive", data.Balance.IsNegative()) }>
+			{ model.FormatMoney(data.Balance) }
 		</p>
-		if data.Allocated > 0 {
+		if data.Allocated.GreaterThan(decimal.Zero) {
 			<p class="text-sm text-muted-foreground mt-1">
-				{ fmt.Sprintf("$%.2f", float64(data.Allocated)/100.0) } in accounts
+				{ model.FormatMoney(data.Allocated) } in accounts
 			</p>
 		}
 	</div>
@@ -161,17 +162,17 @@ templ overviewSpendingCard(data OverviewData) {
 			<div class="space-y-1">
 				<div class="flex justify-between">
 					<span class="text-sm text-green-500 font-medium">Income</span>
-					<span class="text-sm font-bold text-green-500">{ fmt.Sprintf("$%.2f", float64(data.Report.TotalIncome)/100.0) }</span>
+					<span class="text-sm font-bold text-green-500">{ model.FormatMoney(data.Report.TotalIncome) }</span>
 				</div>
 				<div class="flex justify-between">
 					<span class="text-sm text-destructive font-medium">Expenses</span>
-					<span class="text-sm font-bold text-destructive">{ fmt.Sprintf("$%.2f", float64(data.Report.TotalExpenses)/100.0) }</span>
+					<span class="text-sm font-bold text-destructive">{ model.FormatMoney(data.Report.TotalExpenses) }</span>
 				</div>
 				<hr class="border-border"/>
 				<div class="flex justify-between">
 					<span class="text-sm font-medium">Net</span>
-					<span class={ "text-sm font-bold", templ.KV("text-green-500", data.Report.NetBalance >= 0), templ.KV("text-destructive", data.Report.NetBalance < 0) }>
-						{ fmt.Sprintf("$%.2f", float64(data.Report.NetBalance)/100.0) }
+					<span class={ "text-sm font-bold", templ.KV("text-green-500", !data.Report.NetBalance.IsNegative()), templ.KV("text-destructive", data.Report.NetBalance.IsNegative()) }>
+						{ model.FormatMoney(data.Report.NetBalance) }
 					</span>
 				</div>
 			</div>
@@ -191,7 +192,7 @@ templ overviewSpendingByCategoryChart(data OverviewData) {
 				tagColors := make([]string, len(data.Report.ByTag))
 				for i, t := range data.Report.ByTag {
 					tagLabels[i] = t.TagName
-					tagData[i] = float64(t.TotalAmount) / 100.0
+					tagData[i] = t.TotalAmount.InexactFloat64()
 					tagColors[i] = overviewChartColor(i, t.TagColor)
 				}
 			}}
@@ -224,7 +225,7 @@ templ overviewSpendingOverTimeChart(data OverviewData) {
 				var timeData []float64
 				for _, d := range data.Report.DailySpending {
 					timeLabels = append(timeLabels, d.Date.Format("Jan 02"))
-					timeData = append(timeData, float64(d.TotalCents)/100.0)
+					timeData = append(timeData, d.Total.InexactFloat64())
 				}
 			}}
 			@chart.Chart(chart.Props{
@@ -276,8 +277,8 @@ templ overviewBudgetsCard(data OverviewData) {
 								<span class="text-xs text-muted-foreground ml-auto">{ overviewPeriodLabel(b.Period) }</span>
 							</div>
 							<div class="flex justify-between text-xs text-muted-foreground">
-								<span>{ fmt.Sprintf("$%.2f", float64(b.SpentCents)/100.0) } spent</span>
-								<span>of { fmt.Sprintf("$%.2f", float64(b.AmountCents)/100.0) }</span>
+								<span>{ model.FormatMoney(b.Spent) } spent</span>
+								<span>of { model.FormatMoney(b.Amount) }</span>
 							</div>
 							<div class="w-full bg-muted rounded-full h-2">
 								<div class={ "h-2 rounded-full transition-all", overviewProgressBarColor(b.Status) } style={ fmt.Sprintf("width: %.1f%%", pct) }></div>
@@ -309,11 +310,11 @@ templ overviewRecurringCard(data OverviewData) {
 							</div>
 							if r.Type == model.ExpenseTypeExpense {
 								<p class="text-sm font-bold text-destructive shrink-0">
-									{ fmt.Sprintf("$%.2f", float64(r.AmountCents)/100.0) }
+									{ model.FormatMoney(r.Amount) }
 								</p>
 							} else {
 								<p class="text-sm font-bold text-green-500 shrink-0">
-									+{ fmt.Sprintf("$%.2f", float64(r.AmountCents)/100.0) }
+									+{ model.FormatMoney(r.Amount) }
 								</p>
 							}
 						</div>
@@ -348,7 +349,7 @@ templ overviewTopExpensesCard(data OverviewData) {
 								}
 							</div>
 							<p class="text-sm font-bold text-destructive shrink-0">
-								{ fmt.Sprintf("$%.2f", float64(exp.AmountCents)/100.0) }
+								{ model.FormatMoney(exp.Amount) }
 							</p>
 						</div>
 					}

internal/ui/pages/app_space_reports.templ

@@ -9,6 +9,7 @@ import (
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/components/chart"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/layouts"
+	"github.com/shopspring/decimal"
 )
 
 var defaultChartColors = []string{
@@ -72,17 +73,17 @@ templ ReportCharts(spaceID string, report *model.SpendingReport, from, to time.T
 			<div class="space-y-1">
 				<div class="flex justify-between">
 					<span class="text-green-500 font-medium">Income</span>
-					<span class="font-bold text-green-500">{ fmt.Sprintf("$%.2f", float64(report.TotalIncome)/100.0) }</span>
+					<span class="font-bold text-green-500">{ model.FormatMoney(report.TotalIncome) }</span>
 				</div>
 				<div class="flex justify-between">
 					<span class="text-destructive font-medium">Expenses</span>
-					<span class="font-bold text-destructive">{ fmt.Sprintf("$%.2f", float64(report.TotalExpenses)/100.0) }</span>
+					<span class="font-bold text-destructive">{ model.FormatMoney(report.TotalExpenses) }</span>
 				</div>
 				<hr class="border-border"/>
 				<div class="flex justify-between">
 					<span class="font-medium">Net</span>
-					<span class={ "font-bold", templ.KV("text-green-500", report.NetBalance >= 0), templ.KV("text-destructive", report.NetBalance < 0) }>
-						{ fmt.Sprintf("$%.2f", float64(report.NetBalance)/100.0) }
+					<span class={ "font-bold", templ.KV("text-green-500", report.NetBalance.GreaterThanOrEqual(decimal.Zero)), templ.KV("text-destructive", report.NetBalance.LessThan(decimal.Zero)) }>
+						{ model.FormatMoney(report.NetBalance) }
 					</span>
 				</div>
 			</div>
@@ -97,7 +98,7 @@ templ ReportCharts(spaceID string, report *model.SpendingReport, from, to time.T
 					tagColors := make([]string, len(report.ByTag))
 					for i, t := range report.ByTag {
 						tagLabels[i] = t.TagName
-						tagData[i] = float64(t.TotalAmount) / 100.0
+						tagData[i] = t.TotalAmount.InexactFloat64()
 						tagColors[i] = chartColor(i, t.TagColor)
 					}
 				}}
@@ -133,12 +134,12 @@ templ ReportCharts(spaceID string, report *model.SpendingReport, from, to time.T
 					if days <= 31 {
 						for _, d := range report.DailySpending {
 							timeLabels = append(timeLabels, d.Date.Format("Jan 02"))
-							timeData = append(timeData, float64(d.TotalCents)/100.0)
+							timeData = append(timeData, d.Total.InexactFloat64())
 						}
 					} else {
 						for _, m := range report.MonthlySpending {
 							timeLabels = append(timeLabels, m.Month)
-							timeData = append(timeData, float64(m.TotalCents)/100.0)
+							timeData = append(timeData, m.Total.InexactFloat64())
 						}
 					}
 				}}
@@ -189,7 +190,7 @@ templ ReportCharts(spaceID string, report *model.SpendingReport, from, to time.T
 								}
 							</div>
 							<p class="font-bold text-destructive text-sm shrink-0">
-								{ fmt.Sprintf("$%.2f", float64(exp.AmountCents)/100.0) }
+								{ model.FormatMoney(exp.Amount) }
 							</p>
 						</div>
 					}