UK Mortgage Calculator
Calculate your UK mortgage repayment, total interest and full cost using standard UK repayment terms, in pounds.
Monthly repayment
£1,583.51
Total repayment
£475,053
Total interest
£175,053
Interest share
37%
UK mortgages usually charge interest monthly on the outstanding balance. Your actual rate depends on the fixed-rate deal and lender.
How it works
Repayment: M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), r = rate ÷ 12. Income multiple: loan ≈ 4.5 × gross income.
Example: £250,000 at 4.5% over 25 years → £1,389/month repayment.
Last updated: March 2026
How this calculator is verified
Checked by True Calculator automated test suite on
- Formula verified against a published worked example in the automated test suite
- Edge cases (zero, negative, boundary and unit-mismatch inputs) covered by unit tests
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
Use this calculator when you are buying property in the UK, where mortgages are quoted in pounds and typically repaid over 25 years. NRIs purchasing a flat in London or Manchester, Indian students-turned-residents stepping onto the property ladder, and families remitting for a relative's UK purchase all need the same calculation: the monthly repayment and the total cost over the term. The tool follows the standard UK repayment structure, where every monthly payment covers both interest and principal, so the balance falls steadily from month one. Comparing a 25-year and 30-year term shows how much the longer term costs in total interest — the key trade-off before you fix a rate.
How to Use This Calculator
- Step 1: Enter the amount you are borrowing in pounds, such as 250000.
- Step 2: Enter the annual interest rate offered by the lender.
- Step 3: Enter the term in years, typically 25 for a standard UK repayment mortgage.
- Step 4: Read the monthly repayment and the total cost, and compare terms to see how the payment and total interest change.
Worked Example
A buyer in London borrows £250,000 at 4.5% over a 25-year repayment term. Enter 250000 as the loan amount, 4.5 as the annual rate and 25 as the term in years. The monthly repayment is about £1,390, and over the full term the total cost is about £416,859, with total interest of about £166,859. Compare a 30-year term to see the monthly payment fall while the total interest rises, which is the standard trade-off this tool makes visible.
Tips and Common Mistakes
- •Tip 1: UK repayment mortgages pay both interest and principal every month, so the balance falls steadily unlike interest-only terms.
- •Tip 2: Fixed-rate deals in the UK usually last 2, 3 or 5 years before the rate moves to the lender's standard variable rate, so plan beyond the deal period.
- •Tip 3: Lenders stress-test affordability at rates above the advertised one, so check the payment at a higher rate before committing.
- ✗Mistake 1: Entering the term in years when the tool asks for months, which produces a tiny unrealistic monthly repayment.
- ✗Mistake 2: Forgetting arrangement fees and valuation costs, which can run into thousands of pounds on top of the mortgage itself.
Frequently Asked Questions
How is a UK mortgage payment calculated?
The UK calculator uses the same amortising formula with a monthly rate of (annual rate ÷ 12). Your payment is the fixed amount needed to clear principal and interest over the chosen term.
Should I use repayment or interest-only in the UK?
Repayment clears the full balance by the end of the term, so you own the home outright. Interest-only has lower monthly payments but the full loan amount is still due at the end, which suits specific plans.
What does the UK affordability check involve?
Lenders typically cap borrowing at about 4–4.5 times your gross annual income and stress-test payments against a higher rate. Use this calculator to estimate a realistic mortgage based on your income.
Is this UK mortgage calculator free to use?
Yes, True Calculator's UK mortgage calculator is completely free with no sign-up, no app install and no usage limits.
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