UK Mortgage Calculator

Enter the property price, deposit, interest rate, and loan term. The calculator subtracts your deposit from the property price to find your loan amount. It then applies the standard mortgage amortisation formula to calculate a fixed monthly payment that repays both interest and principal over the chosen term.

The results show your estimated monthly payment, total interest, total repayment, and an estimated payoff date. If you add an optional monthly overpayment, the calculator estimates how many years you could save and how much interest you could avoid by paying extra each month.

The calculation includes the loan amount, interest rate, loan term, and any monthly overpayment. It uses a standard repayment mortgage formula with monthly compounding to estimate the payment schedule and total interest paid over the full term.

It does not include mortgage fees, stamp duty, valuation costs, insurance, or council tax. It also does not model variable-rate changes or introductory fixed-rate periods. For those, run multiple scenarios with different rates or terms.

Results assume a fixed interest rate for the full term and payments made monthly. Overpayments are treated as a steady monthly amount added to the standard payment. Totals are rounded to the nearest penny and shown as rounded currency values for readability.

If your rate changes, you take a payment holiday, or you make irregular overpayments, your actual payoff date and total interest will differ. Use this calculator as a planning tool rather than an exact forecast.

Example 1: A £300,000 property with a £30,000 deposit, 4.5% rate, and 25-year term produces a loan of £270,000 and a monthly payment of about £1,500.75. Total interest is roughly £180,224 with a payoff around February 2051.

Example 2: A £450,000 property with a £90,000 deposit, 5.0% rate, and 30-year term produces a payment of about £1,932.56. Adding a £200 monthly overpayment shortens the term to about 24.33 years and saves roughly £72,417 in interest, with payoff around June 2050.

Example 3: A £200,000 property with a £40,000 deposit, 3.75% rate, and 20-year term gives a payment near £948.62 and total interest around £67,669, with payoff around February 2046.