Karcha
A monthly allowance translated into a clear daily spending amount
A native iOS allowance tracker that recalculates daily spending guidance from actual expenses, with check-ins, transaction history, calendar views, and spending insights.
PROJECT OVERVIEW
Karcha is a personal monthly-allowance tracker built around one practical question: how much can I spend today? Users set an allowance, record and edit expenses, check in on spending, and review activity and insights. The interface separates a stable daily recommendation from the live amount remaining for that day, so recording an expense reduces the live balance without moving the target.
THE PROBLEM
A monthly budget can be hard to apply to an individual purchase. Overspending and underspending also need to affect the days ahead without requiring manual adjustments. Karcha turns the remaining monthly allowance into daily guidance and makes the effect of earlier expenses visible.
TECHNICAL APPROACH
A pure Swift budget engine derives its figures from raw expense rows each time they are read. It divides the allowance remaining at the start of the day by the days left, then subtracts today’s spending for the live daily balance. All monetary arithmetic uses integer paise. SwiftData stores allowances and expenses; a shared BudgetReader connects persistence to the engine, and Swift Charts renders insights. Month rollover asks for a fresh allowance rather than silently carrying the prior one forward.
PROJECT OUTCOME
Implemented a native app with expense entry, activity history, daily check-ins, calendar exploration, and spending insights. The central engineering result is one deterministic calculation shared across screens: edited or backdated expenses automatically affect later guidance without storing a separate carry-forward balance.