Mortgage Repayment Calculator
Work out the monthly repayments on a UK mortgage for any loan amount, rate, and term. The calculator uses the standard annuity formula used by UK lenders and shows the total interest you would pay over the life of the loan — useful when comparing a 5-year fixed-rate mortgage against a tracker.
How is this calculated?
Repayments use the annuity (PMT) formula: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the loan amount, r is the monthly rate (annual rate ÷ 12), and n is the number of monthly payments. This is the same approach UK lenders use for capital-and-interest mortgages and assumes the rate is held constant for the period shown. Interest-only mortgages, where you only service interest each month, are not modelled here.
Frequently Asked Questions
How are UK mortgage repayments calculated?
UK lenders use the annuity formula. Each monthly payment covers the interest accrued on the outstanding balance plus a slice of the capital. Early in the term the interest portion is largest; as the balance falls, more of each payment chips away at the principal.
What is a typical UK mortgage rate in 2026?
Average 2-year and 5-year fixed rates in 2026 sit broadly in the 4%–5% range, tracking movement in the Bank of England base rate. Lower loan-to-value bands (60% or below) usually get the keenest pricing. Always compare the headline rate alongside fees and the SVR you revert to.
Can I overpay my UK mortgage?
Most lenders allow overpayments of up to 10% of the outstanding balance per year on a fixed-rate deal without an early repayment charge. Variable and tracker products are usually fully flexible. Overpaying reduces the principal earlier, cutting both the term and the total interest paid.
How much does a £350,000 mortgage cost per month?
At 4.5% over 30 years a £350,000 mortgage costs roughly £1,773 per month, with about £288,400 of interest paid over the term. Shortening to a 25-year term at the same rate raises the monthly payment to about £1,946 but saves around £64,000 in total interest.
Last updated: May 2026 · Rates sourced from HMRC