Mortgage Repayment Calculator

Work out monthly payments, total interest and a full amortisation schedule for any UK mortgage.

Mortgage Details
£
The amount you are borrowing, after deposit.
%
1 yr20 yr40 yr
£
Repayment Summary
Monthly Payment
£0.00
Total Interest
£0.00
Total Repaid
£0.00
Capital
Interest
Frequently Asked Questions

A standard repayment mortgage uses the annuity 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 total number of monthly payments (term in years × 12). Each payment covers some interest and some capital, with the proportion shifting towards capital over time.

On a repayment mortgage every monthly payment chips away at the capital balance, so by the end of the term the loan is fully paid off. On an interest-only mortgage you only pay the interest each month and still owe the full original loan amount at the end of the term, when it must be repaid in full (usually by selling the property or from savings/investments).

Even small regular overpayments make a big difference because they reduce the capital balance early, when most of your interest is being charged. £100 a month extra on a 25-year, £200,000 mortgage at 5% saves roughly £30,000 in interest and clears the mortgage about 4 years early. Most UK lenders allow 10% overpayment per year without early repayment charges.

A shorter term means higher monthly payments but much less interest paid overall and quicker outright ownership. A longer term lowers monthly payments and improves affordability but costs significantly more in interest. Many borrowers compromise with 25–30 years and make voluntary overpayments when they can afford to.

No — this tool focuses on the monthly repayment, total interest and balance schedule based on capital, rate and term only. For purchase costs use our Stamp Duty Calculator, and for affordability checks use our Mortgage Affordability Calculator. Always factor in arrangement fees, valuation fees and any early repayment charges (ERCs) when comparing deals.
Quick Reference

Typical UK fixed terms: 2, 3, 5 or 10 years (the “deal period”), then revert to SVR.

Standard amortisation: 25 years is common; 30–40 year terms increasingly available.

10% overpayment rule: Most lenders allow up to 10% of the balance overpaid each year without ERCs.

Early repayment charges: Usually 1–5% during a fixed deal period, falling each year.

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