See how one-off or monthly overpayments cut your mortgage term and interest with our handy Mortgage Overpayment Calculator.
Quickly see how one-off or monthly overpayments cut the interest you pay and shorten your mortgage term.
This tool estimates how mortgage overpayments can reduce your total interest and bring forward your mortgage end date. It supports one-off lump sums, regular monthly overpayments, and an offset comparison so you can decide the most efficient use of spare cash.
Displays in the chosen currency (no FX conversion).
Switch between repayment and interest-only calculations.
Outstanding balance today.
Nominal rate; monthly compounding assumed.
Time left until mortgage end.
Extra amount added each month.
Applied immediately; reduces balance before the first payment.
Annual cap as % of starting balance (set 0 to ignore).
Instead of overpaying, place this into an offset balance. It reduces interest like a tax-free "return" equal to your mortgage rate while keeping funds accessible.
Required monthly payment—
Interest (baseline)—
Interest with overpayments—
Interest saved (overpay)—
Term with overpayments—
Term reduction—
Interest with offset—
Interest saved (offset)—
Recommendation—
Repayment mode: fixed payment reduces balance to zero by term. Interest-only mode: monthly payment covers interest only; balance is due at the end unless cleared earlier by overpayments. Offset series on the chart shows the "interest-bearing" balance (balance minus offset).
