Skip to content
Think carefully before securing debts against your home. FCA Register
U
Request Callback

Mortgage Overpayment Calculator UK

Estimate the possible term and interest impact of a regular overpayment.

This calculator is for illustration only and provides estimates for general information. It is not mortgage advice, a mortgage offer, a decision in principle or a guarantee of rates, fees, eligibility or savings.

Mortgage Overpayment Calculator

See how monthly overpayments could shorten your term and reduce interest.

Current monthly payment
£—
Time saved
— years
Interest saved
£—
New payoff
— mo

Estimate only. Assumes your interest rate and required monthly payment stay unchanged and that overpayments reduce the term. Check your mortgage terms for overpayment allowances and possible Early Repayment Charges.

Download PDF

Keep a copy of this estimate

Email yourself a PDF summary of the figures currently shown on this calculator.

Calculator results are estimates only. Actual rates, fees, eligibility and products depend on your circumstances and lender criteria.

Request adviser callback Compare remortgage impact
SSL Secure Form submissions are handled over HTTPS FCA Registered FCA registered: TBC Trustpilot reviews Review profile placeholder

How overpayments work

An overpayment pays down extra principal, so subsequent months may charge interest on a smaller balance. Depending on your balance, rate and term, regular or one-off overpayments can reduce the mortgage term under the calculator assumptions.

Before you overpay

  • Check your lender’s annual overpayment allowance during the fixed period.
  • Keep an emergency buffer in instant-access savings.
  • Compare with high-rate savings / employer pension matching.
  • Ask the lender how applying overpayments to “reduce term” or “reduce payment” would affect your mortgage.

Speak to an adviser before making changes

If overpayments, remortgaging or savings options are hard to compare, request a callback. A mortgage adviser or broker partner can discuss your circumstances; this calculator does not provide advice.

Frequently asked questions

How much can I overpay without a charge? +
Most UK lenders allow up to 10% of the outstanding balance per calendar year without triggering an Early Repayment Charge during a fixed deal. Always check your mortgage offer.
Is overpaying always worth it? +
Not always. Overpayments can reduce interest and term in the calculator, but you should check charges, keep an emergency cash buffer, and consider savings or pension contributions depending on your circumstances.
Reduce term or reduce monthly payment? +
Most lenders default to keeping the term the same and shrinking the next monthly payment slightly. To reduce term, ask the lender to apply overpayments to “reduce term” rather than “reduce balance”.
What about when my fixed deal ends? +
Outside the fixed period most lenders allow unlimited overpayment with no ERC. Many borrowers ramp up overpayments at that point.

Suggested next steps

Related calculators and guides

Offset Mortgage Calculator GuideUnderstand how an offset mortgage could affect interest estimates when savings are linked to a mortgage balance.Mortgage Term Calculator GuideCompare estimated mortgage payments over different terms and understand the trade-off with total interest.Fixed Rate Mortgage Calculator GuideEstimate monthly payments for a fixed-rate mortgage and compare the effect of term, balance and rate assumptions.

Calculator-led mortgage planning

UK Mortgage Calculators is centred on practical estimation tools. The pages help you model cautious scenarios before you decide whether to request a broker or adviser callback.