A small regular overpayment can knock years off your mortgage and save a fortune in interest. Enter your balance, rate, term and a monthly overpayment to see exactly how much you save and when you'd be mortgage-free.
Repayment mortgage · monthly overpayment
Mortgage interest is charged on the outstanding balance. Every pound you overpay comes straight off that balance, so all the future interest it would have attracted simply disappears. Because the saving compounds over the remaining term, even modest overpayments early on have an outsized effect.
| Overpayment / month | Interest saved* | Years saved* |
|---|---|---|
| £100 | ~£26,000 | ~4 years |
| £200 | ~£45,000 | ~7 years |
| £300 | ~£58,000 | ~9 years |
| £500 | ~£76,000 | ~12 years |
*Illustrative, on a £200,000 mortgage at 5% over 25 years.
Most fixed-rate deals cap penalty-free overpayments at 10% of the balance a year. Exceed that during the fixed period and you may face an early repayment charge. Once you're on a variable rate or between deals, the limit usually disappears. Compare the underlying loan on the mortgage calculator or model a new deal on the remortgage calculator.
The savings compound. On a £200,000 mortgage at 5% over 25 years, overpaying £200 a month can save around £45,000 in interest and clear the loan about seven years early.
Usually, if your rate beats what savings earn after tax. Overpaying gives a guaranteed, tax-free return equal to your mortgage rate — but keep an emergency fund and clear costlier debt first.
Most fixed deals allow up to 10% of the balance a year penalty-free. Exceed that during a fix and an early repayment charge may apply — check your terms.
Both shorten the mortgage. Overpaying keeps flexibility — you can stop any time. Shortening the term locks in a higher payment but can secure the saving. Overpaying is usually the safer first move.
