UK Mortgage Calculator

Estimate your monthly repayment and the total interest you'll pay on a repayment mortgage.

Rates: 2026/27 tax year · effective 2026-04-06 · updated 2026-08-16
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Estimate only — double-check the figures before relying on them.

How it works

Enter the loan amount, the annual interest rate and the term in years. We use the standard amortisation formula in your browser to show the monthly payment, total paid and total interest.

In detail

A repayment mortgage pays off both interest and capital, so the balance reaches zero at the end of the term. This calculator uses the standard amortisation formula:

M = P × r(1+r)n ÷ ((1+r)n − 1)

where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments (term × 12).

What affects your payment?

  • Interest rate: the single biggest lever — a 1% change on a large loan moves the monthly figure noticeably.
  • Term: a longer term lowers the monthly payment but increases total interest.
  • Deposit: a bigger deposit means a smaller loan and lower payments.

This is an estimate for a capital-and-interest repayment mortgage. It excludes arrangement fees, insurance and tax. Remember to budget for stamp duty on the purchase. Always compare quotes from regulated lenders.

This calculator provides estimates only. Tax rules, bands and rates change every tax year — verify against the official source (HMRC) or a qualified adviser before relying on any number.

FAQ

What is a repayment mortgage?

A repayment (capital-and-interest) mortgage pays off the loan in full by the end of the term, provided all payments are made.

Does this include stamp duty or fees?

No. It estimates the loan repayment only. You should also budget for stamp duty, arrangement fees and insurance.

How can I lower my monthly payment?

Increase your deposit, extend the term, or secure a lower interest rate. Extending the term reduces the monthly cost but raises total interest.

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Written by the QuickCalc Editorial Team. Last reviewed: August 2026 against HMRC rates for the 2026/27 tax year.

QuickCalc is an independent calculator site. Figures are estimates for guidance only and are not professional tax, financial or legal advice. Always verify with the official source (HMRC) or a qualified adviser before filing or making decisions.