UK mortgage calculator for monthly repayments
Add the property price, deposit, rate and term, and this UK mortgage calculator shows your monthly repayment, total interest and the full amount you'll repay.
Last updated Updated for 2026
Estimates only. This is not tax, legal or financial advice. Stamp Duty, arrangement fees and other buying costs are not included.
How to use the UK mortgage calculator
- Enter the property price.
- Enter your deposit as a percentage of the price, for example 10.
- Enter the mortgage rate and the term in years.
- Press Calculate payment to see the monthly repayment, the loan amount and the total interest.
How the UK mortgage calculator works
Most UK homebuyers take a repayment mortgage, where each monthly payment covers that month's interest and pays off part of the loan. The calculator finds the fixed payment that clears the loan exactly by the end of the term.
UK deals usually fix the rate for two or five years and then move to the lender's standard variable rate. This calculator assumes one rate for the whole term, so use it to compare deals and to stress-test higher rates. Stamp Duty, arrangement fees and other buying costs are not included.
Formula
Loan = price × (1 − deposit % ÷ 100). Monthly rate m = annual rate ÷ 1200 and number of payments n = years × 12.
Monthly repayment = L × m × (1 + m)^n ÷ ((1 + m)^n − 1). Total interest = repayment × n − L.
Example
A £300,000 home with a 10% deposit needs a £270,000 mortgage. At 4.5% over 25 years, the monthly repayment is about £1,500.75, and you repay about £450,224 in total, of which about £180,224 is interest.
Stretching the same mortgage to 35 years lowers the repayment to about £1,277.79 a month, but total interest climbs to about £266,673.
Tips and common mistakes
A bigger deposit can unlock better rates
Lenders price mortgages by loan-to-value. Moving from a 90% to a 75% mortgage often brings a noticeably lower rate.
Stress-test your budget
Try a rate two or three points higher to see what could happen to your payment when a fixed deal ends.
Budget for Stamp Duty
Stamp Duty Land Tax may be due in England and Northern Ireland on top of your deposit; Scotland and Wales have their own property taxes.
Know your monthly income
Lenders often lend around four to four and a half times income. See your pay after tax with the UK take-home pay calculator.
Comparing other borrowing
For personal loans and car finance, the EMI calculator works out the monthly cost the same way.
Frequently asked questions
Does it work for interest-only mortgages?
No. It is for repayment mortgages. With interest-only, you pay just the interest each month and still owe the whole loan at the end.
Is Stamp Duty included?
No. Stamp Duty and fees are paid upfront and don't change the monthly repayment.
How do fixed-rate deals affect the result?
The calculator assumes one rate for the full term. When a fixed deal ends, your payment changes to reflect the new rate.
Can I see the effect of overpayments?
Not here. Many lenders let you overpay up to 10% a year without charges, which shortens the term and cuts total interest.