UK Mortgage Calculator 2026
Last verified · Methodology
Enter your property price, deposit, interest rate, and term to calculate your monthly mortgage payment, total cost, and total interest. Supports both repayment and interest-only mortgages. Figures reflect standard UK amortisation.
Mortgage Details
Calculations use standard amortisation formula. Does not include buildings insurance, life insurance, arrangement fees, or SDLT. Always obtain a mortgage illustration (ESIS) from a regulated lender or broker. Does not constitute financial advice.
How the Calculation Works
For a repayment mortgage, the monthly payment is calculated using the standard amortisation formula. The loan (principal minus deposit) is divided into equal monthly instalments where each payment covers both interest and a growing share of the capital. Early payments are mostly interest; later payments are mostly capital.
The formula is: M = P x r(1+r)^n / ((1+r)^n - 1), where P is the mortgage amount, r is the monthly interest rate (annual rate divided by 12), and n is the total months.
For an interest-only mortgage, the monthly payment is simply the loan amount multiplied by the annual interest rate, divided by 12. The capital remains unchanged throughout the term. Most UK lenders require a credible repayment strategy before approving interest-only for residential mortgages.
Your loan-to-value (LTV) ratio is the mortgage as a percentage of the property value. The LTV determines which rate tiers you can access: the lower the LTV, the better the deals available. A 60% LTV (40% deposit) typically unlocks the best rates; 90% and 95% LTV products are available but at a significant premium.
| Loan Amount | Monthly Payment | Total Interest |
|---|---|---|
| £150,000 | £921 | £126,270 |
| £200,000 | £1,228 | £168,360 |
| £250,000 | £1,535 | £210,450 |
| £300,000 | £1,842 | £252,540 |
| £400,000 | £2,456 | £336,720 |
| £500,000 | £3,070 | £420,900 |
For a repayment mortgage, the monthly payment is calculated using the standard amortisation formula: M = P x r(1+r)^n / ((1+r)^n - 1), where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments (years x 12). For interest-only, the payment is simply: P x annual rate / 12.
The most common mortgage term in the UK is 25 years, though terms from 5 to 40 years are available. Longer terms reduce monthly payments but significantly increase total interest paid. Many borrowers choose 25 or 30 years for affordability, then overpay when finances allow to reduce the term.
Most lenders require a minimum 5% deposit (95% LTV), though the best rates are typically available at 60% LTV or below. With a 5-10% deposit you may face a higher mortgage rate and possibly need to use the Mortgage Guarantee Scheme. First-time buyers can sometimes use shared ownership or Help to Buy schemes to purchase with a smaller deposit.
A repayment mortgage reduces your balance every month, so the loan is fully paid off at the end of the term. An interest-only mortgage means your monthly payment covers only the interest; the original capital remains outstanding and must be repaid in full at the end, typically from savings or by selling the property. Most residential mortgages in the UK are repayment; interest-only is more common for buy-to-let.
A fixed rate gives certainty: your payment will not change during the fixed period regardless of Bank of England base rate changes. Two-year fixes offer flexibility to remortgage sooner; five-year fixes provide longer certainty but may carry an early repayment charge (ERC). Tracker and variable rate mortgages follow the base rate and can fall as well as rise. The right choice depends on your risk tolerance and how long you plan to stay in the property.
Beyond the monthly mortgage payment, budget for: Stamp Duty Land Tax (unless you are a first-time buyer under the threshold), solicitor or conveyancer fees (typically £1,000 to £2,000), survey fees (£300 to £1,500), mortgage arrangement fee (often £500 to £2,000 or added to the loan), buildings insurance (required by lenders), and ongoing maintenance costs. A mortgage broker can help compare the total cost of different deals.