Mortgage & Loan Calculator UK

Three free UK calculators in one: work out mortgage repayments, loan repayments, and compound interest on savings or investments. Switch tabs below — everything runs in your browser, no sign-up.

This assumes one fixed rate for the whole term, for simplicity. Real mortgages often have an initial fixed or discounted period followed by a different rate — check the full terms before assuming this rate applies throughout.

This assumes a constant growth rate every month, which real investments never do — returns vary year to year and can be negative. Treat the result as an illustration of how contributions and time interact, not a forecast. Read more about investing basics.

How the UK mortgage calculator works

Enter the property price, your deposit as a percentage, an interest rate and the mortgage term in years. The calculator works out your loan amount, your loan-to-value (LTV), the estimated monthly repayment, and the total interest over the full term. A bigger deposit lowers your LTV, which generally unlocks better mortgage rates — so it’s worth trying a few deposit sizes to see the effect on the monthly cost. For first-time buyers, our guide on saving for a house deposit covers the wider costs to plan for.

Working out loan repayments

The loan tab uses the standard repayment formula to estimate the monthly payment on a personal loan, car loan or similar, based on the amount, the APR and the term. It also shows the total you’ll repay and how much of that is interest — useful for comparing borrowing options or deciding whether to overpay. If you’re juggling several debts, our guide on debt payoff methods explains which to clear first.

Understanding compound interest

The compound interest tab shows how a starting amount plus regular monthly contributions could grow over time at a given annual rate. Because you earn returns on your previous returns, growth accelerates the longer money stays invested — which is why starting earlier matters so much. Our guide on compound interest explains the idea in plain English, and the stocks and shares ISA guide covers the tax-efficient way to hold longer-term investments in the UK.

Frequently asked questions

How much can I borrow for a mortgage in the UK?+

Lenders typically use an income multiple and an affordability assessment of your wider finances, so there’s no single figure. This calculator estimates the repayment on a given loan amount; how much a lender will offer you depends on your income, outgoings and credit profile.

Is this mortgage calculator accurate?+

It gives a solid estimate based on a single fixed rate across the whole term. Real UK mortgages often have an initial fixed or discounted period followed by a different rate, and may include fees, so treat the result as a guide rather than a precise quote.

How is compound interest calculated?+

Each period, interest is added to your balance, and the next period’s interest is calculated on that larger balance — so you earn returns on your returns. This calculator compounds monthly using your starting amount, monthly contributions and annual rate.

What does loan-to-value (LTV) mean?+

LTV is your mortgage loan as a percentage of the property price. A smaller deposit means a higher LTV; a bigger deposit means a lower LTV, which usually qualifies you for better interest rates.

Is the calculator free and private?+

Yes — it’s free, needs no sign-up, and every calculation runs in your browser. Nothing you enter is sent anywhere or stored.