How mortgage overpayments work
Regular overpayments reduce the capital balance sooner. That means less interest is charged in later months and the mortgage may finish earlier. This calculation assumes your normal payment stays unchanged and every overpayment reduces capital immediately.
Check your mortgage agreement first
Some UK mortgages limit penalty-free overpayments or apply an early repayment charge. Limits are product-specific, so check your latest mortgage statement or ask your lender before changing payments. Keeping accessible emergency savings may also be more important than overpaying.
Assumptions
- The interest rate and monthly overpayment remain constant.
- Interest is calculated monthly and fees are excluded.
- The normal repayment is recalculated from the balance, rate and remaining term entered.
- Results are estimates, not advice or a lender statement.
Reviewed by the Properties & Homes editorial team
Last reviewed: 14 August 2026.
Next, compare the underlying payment in our mortgage repayment calculator.