Calculator Methodology
Review the formulas, input handling, assumptions, limitations, and quality checks used by every browser-based money.you calculator.
Formulas are visible by design
Calculators run locally in the browser and use only the labeled fields. Currency results are rounded for display. Intermediate calculations retain precision. We do not send calculator inputs to the server.
Core methods
Loan payments use the standard fixed-payment amortization formula. Debt payoff iterates monthly interest and payments with a safety limit. Compound growth assumes monthly compounding and end-of-month contributions. The budget and net-worth tools use direct addition and subtraction.
Limits
Results are scenarios, not quotes, forecasts, or advice. Taxes, fees, daily interest, variable rates, payment allocation, promotional terms, and local law can change real outcomes. Zero or impossible inputs are rejected rather than silently producing a misleading answer.
How calculator quality is checked
Input validation
Fields limit impossible or unsafe ranges where practical, and the result explains when an entered payment or term cannot produce a meaningful answer.
Independent recalculation
Core formulas are tested with known examples, zero-rate cases, boundary values, and hand-checkable inputs before a calculator is released.
Interpretation before action
Every tool pairs the number with its limits and a relevant guide because a correct calculation can still support a poor decision when inputs are incomplete.
Related policies and practical next steps
Test the documented approach with a real formula and its explanation. Use the loan payment calculator; Read how compound returns work.