Mortgage overpayment calculator
See how much interest you save, and how much sooner you are mortgage-free, by overpaying.
Assumes the rate stays the same and overpayments reduce the term, not the monthly payment.
Why overpaying works
Mortgage interest is charged on the balance you still owe. Every extra pound you pay reduces that balance straight away, so less interest is charged every month after, for the rest of the term.
Overpaying early in the mortgage saves the most, because the balance (and the interest on it) is highest at the start.
Before you overpay
Most fixed and tracker deals allow overpayments of up to 10% of the balance each year; above that you may pay an early repayment charge. It usually makes sense to clear more expensive debts and keep an emergency fund first.
Frequently asked questions
Is it better to overpay or save?
Overpaying saves interest at your mortgage rate, risk-free. If you can earn more than that rate after tax in savings, saving can come out ahead, and savings stay accessible.