Mortgage Calculator UK

How the mortgage calculation works

The calculator applies the standard repayment formula: monthly payment M = P × r ÷ (1 − (1 + r)^−n). For the default example — a £250,000 home with a £25,000 deposit — the loan is £225,000 (90% LTV). At an illustrative 4.5% over 25 years (300 payments), the monthly payment is £1,250.62, the total repaid is £375,187 and the total interest is £150,187. Change any input and the trade-offs appear at once: a bigger deposit cuts both the loan and the LTV band, a longer term cuts the monthly figure while adding interest, and a higher rate moves the payment more than most borrowers expect.

Quick reference

• £200,000 at 4.5% over 25 years — £1,111.66 a month
• £225,000 at 4.5% over 25 years — £1,250.62 a month
• £180,000 at 4.5% over 25 years — £1,000.50 a month
• £315,000 at 4.5% over 25 years — £1,750.87 a month

Rates above are illustrative only, not quoted or promised. Before offering, check the product fee, whether the rate is fixed or variable, and what the lender's affordability and stress tests would do to the amount offered.