UK Mortgage Calculator
Work out monthly payments on a UK mortgage in pounds for both repayment and interest-only deals, along with your loan-to-value (LTV) ratio and the total cost of borrowing over the term. See how your deposit size moves you into better LTV bands.
How to Use
- Enter the property price in pounds.
- Enter your deposit — this sets your loan-to-value (LTV) ratio.
- Enter the mortgage interest rate offered by the lender.
- Enter the term in years (25 is the UK standard, though 30-40 is increasingly common).
- Compare the repayment and interest-only monthly figures and the total cost shown.
Show Work
LTV bands
About the UK Mortgage Calculator
The UK Mortgage Calculator is a free tool for personal-finance and money decisions. It runs right in your web browser, so there is nothing to download. Work out monthly payments on a UK mortgage in pounds for both repayment and interest-only deals, along with your loan-to-value (LTV) ratio and the total cost of borrowing over the term. See how your deposit size moves you into better LTV bands.
How it works
Type your numbers into the boxes. The answer shows up right away — you do not have to press a button. If you change a number, the answer changes too. So you can try different numbers and watch what happens, or check an answer you worked out yourself. Just make sure each box has the right kind of number in it.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
What is LTV and why does it matter?
Loan-to-value is the mortgage amount as a percentage of the property price — a £30,000 deposit on a £300,000 home is a 90% LTV. Lenders price by LTV band: at 60% LTV or below you get the best rates, while above 90% rates rise and choice narrows. Building a larger deposit to cross a band (e.g. from 90% to 85%) can meaningfully cut your rate.
Repayment vs interest-only — which should I choose?
On a repayment mortgage each monthly payment covers interest plus a slice of the capital, so the balance reaches zero by the end of the term. Interest-only payments cover only the interest, so they are lower but the full balance is still owed at the end and must be repaid from savings, investments, or sale. Most UK residential borrowers are on repayment; interest-only is more common for buy-to-let.
How long are UK mortgage terms?
Twenty-five years has been the traditional standard, but 30, 35, and even 40-year terms are now widely offered to keep monthly payments affordable. A longer term lowers the monthly payment but increases the total interest paid over the life of the loan, which this calculator makes visible.
Does this include Stamp Duty or other fees?
No — the figures cover the mortgage payment and total interest only. Stamp Duty Land Tax, valuation and arrangement fees, conveyancing, and broker fees are paid separately and vary by price and circumstance. Budget for these up-front costs alongside your deposit. This is an estimate to plan with, not a formal mortgage illustration.
Are UK mortgage rates fixed for the whole term?
Usually not. Most UK borrowers take a fixed-rate deal for 2, 3, 5, or 10 years and then move onto the lender's higher standard variable rate (SVR) or remortgage to a new fix. This tool assumes a single rate for the whole term, so re-run it with your expected rate after the fixed period to see how payments could change.
How do I use the UK Mortgage Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
Checking affordability before viewing
Try different property prices to see the monthly payment that fits your budget before booking viewings.
Sizing your deposit to an LTV band
Adjust the deposit to see when you cross into a cheaper LTV band and qualify for a better rate.
Comparing repayment and interest-only
See both monthly figures side by side to weigh lower payments now against owing the full balance later.
Stress-testing a rate rise
Re-run at a higher rate to check whether payments would still be affordable when your fixed deal ends.
Choosing a mortgage term
Compare a 25-year versus a 35-year term to balance monthly affordability against total interest paid.
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