Money & shopping
Loan overpayment calculator
Compare an additional monthly payment with a fixed-rate repayment schedule.
A clear answer. Here’s how.
Calculates the original amortising monthly payment using annual nominal interest divided by 12. Adds your extra payment each month and adjusts the last payment to clear the balance. Compares term and full-precision interest with the original schedule. Excludes fees, penalties and lender rounding.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Loan principal
- 10000
- Nominal annual interest (%)
- 6
- Original term (months)
- 36
- Extra monthly payment
- 50
Example result
| Month | Payment | Interest | Principal | Remaining balance |
|---|---|---|---|---|
| 1 | 354.219374516 | 50 | 304.219374516 | 9,695.78062548 |
| 2 | 354.219374516 | 48.4789031274 | 305.740471388 | 9,390.0401541 |
| 3 | 354.219374516 | 46.9502007705 | 307.269173745 | 9,082.77098035 |
| 4 | 354.219374516 | 45.4138549018 | 308.805519614 | 8,773.96546074 |
| 5 | 354.219374516 | 43.8698273037 | 310.349547212 | 8,463.61591353 |
Original scheduled payment 304.22. Term shortened by 5 months. Total paid 10,807.27. Interest with extra payments 807.27; modelled interest saving 144.62. Full-precision arithmetic; lender rounding and fees can differ.