Quick guide
How to use this calculator
- Enter every amount in one consistent currency.
- Use the nominal annual rate and whole-number monthly timing requested by each label.
- Read the result together with the stated timing convention and calculator-specific exclusions.
Calculation method
Calculation method
Each month applies interest, the original scheduled payment, and the entered extra amount; the final payment is capped at the amount actually due.
Entered monetary components are aggregated as exact fixed decimals. Amortization keeps full calculation precision and rounds only for presentation; a nonzero supported result is never displayed as zero.
Worked example
Worked example
Adding 200 per month to a 120,000 zero-rate, 120-month loan changes the payoff from 120 months to 100 months.
Each month applies interest, the original scheduled payment, and the entered extra amount; the final payment is capped at the amount actually due.
Supported inputs
Precision and limits
Visible input limits
Amounts are capped at 1e12, nominal annual rates at 1000%, schedules at 1,200 months, and fixed-decimal inputs at 12 decimal places.
Estimate, not an offer
Results model only the entered values. A lender or contract may use different payment dates, day counts, compounding, fee treatment, statement rounding, or allocation rules.
International scope
No currency, country, tax, credit-scoring system, consumer-credit law, or lender policy is assumed. Location-dependent amounts must be entered explicitly.
Calculator-specific assumptions
Confirm how a lender applies extra payments and whether a penalty applies. The model assumes every extra amount reduces principal in the same month.