About the UK Mortgage Calculator
This UK mortgage calculator works out your monthly mortgage payment in pounds for either a repayment (capital and interest) or an interest-only mortgage, along with the total interest over the term, your loan-to-value ratio and the stamp duty due on the purchase. It also estimates how much you could borrow using the income multiple most UK lenders apply — typically around 4 to 4.5 times your gross annual income, sometimes higher for high earners.
It is aimed at first-time buyers checking what they can afford, home movers planning a budget and anyone comparing deals from a broker. A stress-tested payment at 3 percentage points above your rate shows how a rate rise at the end of a fixed deal would feel. The Bank of England withdrew its formal 3-point affordability test on 1 August 2022, but lenders must still check under FCA responsible-lending rules that you could cope with higher rates, and many still use a stress margin, so this remains a useful guide rather than any single lender’s exact test.
Stamp Duty Land Tax uses the England and Northern Ireland rates in force from 1 April 2025 (unchanged for the 2026/27 tax year) for a main residence, including first-time buyer relief on homes up to £500,000. Scotland (LBTT) and Wales (LTT) use different rules, and the 5% surcharge on additional properties is not included.
With the default inputs, the monthly payment is £1,334.00. Change any value above to recalculate instantly.
How to use the uk mortgage calculator
- 1Enter the property price and your deposit.
- 2Enter the interest rate and mortgage term, and choose repayment or interest only.
- 3Add your gross income (and a joint applicant’s) and the lender’s income multiple.
- 4Tick first-time buyer if it applies, to use first-time buyer stamp duty relief.
- 5Check the monthly payment, the stress-tested payment and your borrowing limit.
Formula and method
For a repayment mortgage the monthly payment uses the standard annuity formula, where P is the mortgage (price minus deposit), r the monthly rate (annual rate ÷ 12) and n the number of monthly payments. For interest only, each payment is simply one month’s interest on the full balance, and the capital is repaid at the end of the term.
Maximum borrowing multiplies combined gross income by the lender’s multiple; real lenders also check outgoings and credit. Stamp duty is charged in slices: for a main home in England or Northern Ireland from April 2025, 0% up to £125,000, 2% to £250,000, 5% to £925,000, 10% to £1.5 million and 12% above. First-time buyers pay 0% up to £300,000 and 5% on £300,001–£500,000 when the price is £500,000 or less.
- M
- Monthly mortgage payment
- P
- Mortgage amount (property price − deposit)
- r
- Monthly interest rate (annual rate ÷ 12 ÷ 100)
- n
- Number of monthly payments (term × 12)
Worked examples
£300k first home, £60k deposit, 4.5% over 25 years
A £240,000 repayment mortgage at 4.5% over 25 years costs £1,334.00 a month and about £160,199 in interest. On £55,000 income a 4.5× multiple allows about £247,500, so it fits. As a first-time buyer on a £300,000 home you pay no stamp duty.
Interest-only £300k loan at 5%, home mover
Interest only on £300,000 at 5% is £300,000 × 5% ÷ 12 = £1,250 a month, or £375,000 over 25 years, with the full £300,000 still owed at the end. Stamp duty on £400,000 is 2% of £125,000 (£2,500) plus 5% of £150,000 (£7,500) = £10,000.
Joint buyers, £450k first home, 30-year term
With a 10% deposit the mortgage is £405,000 (90% LTV), costing £2,124.89 a month at 4.8% over 30 years. Combined income of £90,000 × 4.5 = £405,000, exactly the amount needed. First-time buyer relief means stamp duty is 5% of the £150,000 above £300,000 = £7,500.
Frequently asked questions
How much can I borrow for a mortgage in the UK?+
Most lenders offer around 4 to 4.5 times your gross annual income (joint incomes are added), and some go to 5 or 5.5 times for higher earners or certain professions. Loans at 4.5 times income or more are restricted by the Bank of England’s loan-to-income flow limit to about 15% of new mortgages, so they are rationed. The final amount also depends on your outgoings, debts, credit record and deposit.
What deposit do I need for a UK mortgage?+
The minimum is usually 5% of the price (95% LTV), but rates improve at 10%, 15%, 25% and 40% deposits. Interest-only mortgages normally need at least 25% and a credible repayment plan.
How much stamp duty will I pay in 2026?+
In England and Northern Ireland, home movers pay 0% up to £125,000, 2% to £250,000, 5% to £925,000, 10% to £1.5 million and 12% above. First-time buyers pay nothing up to £300,000 and 5% up to £500,000; above £500,000 standard rates apply.
What is a mortgage stress test?+
Lenders check that you could still afford payments if rates rose. The Bank of England’s formal test (a 3 percentage point rise on the reversion rate) was withdrawn from 1 August 2022, but FCA rules still require lenders to consider likely rate rises, and each lender now sets its own stress rate. This calculator shows the payment at your rate plus 3 points as a cautious benchmark.
Should I choose a 25 or 35 year mortgage term?+
A longer term lowers the monthly payment but adds considerably more interest over the life of the loan. Many borrowers take a longer term for affordability and overpay when they can, as most deals allow 10% overpayments a year.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.