Mortgage repayment calculator
See what your mortgage will cost each month and in total. Change the rate or term to compare deals.
How mortgage repayments are calculated
For a repayment mortgage, lenders use the standard formula:
M = P × r ÷ (1 − (1 + r)−n)
where P is the loan, r is the monthly interest rate (the annual rate ÷ 12) and n is the number of monthly payments. Early on, most of each payment is interest. As the balance shrinks, more of each payment goes towards the loan.
Monthly payments by loan size
Over 25 years on a repayment mortgage:
| Loan | At 4% | At 4.5% | At 5% |
|---|---|---|---|
| £150,000 | £791.76 | £833.75 | £876.89 |
| £200,000 | £1,055.67 | £1,111.66 | £1,169.18 |
| £250,000 | £1,319.59 | £1,389.58 | £1,461.48 |
| £300,000 | £1,583.51 | £1,667.50 | £1,753.77 |
Ways to reduce what you pay
- Bigger deposit: a lower loan-to-value (LTV), such as 75% instead of 90%, usually gets a cheaper rate.
- Remortgage before your deal ends: if you don't, you'll usually move onto the lender's much higher standard variable rate.
- Overpay: even small regular overpayments can take years off the term.
- Compare the whole cost: a deal with a low rate but a big arrangement fee isn't always cheaper.
Buying? Work out your stamp duty too.
Frequently asked questions
What are the monthly payments on a £200,000 mortgage?
On a 25-year repayment mortgage at 4.5%, a £200,000 loan costs about £1,111.66 a month. Over the full term you'd pay about £133,500 in interest. At 5% it rises to about £1,169 a month.
What is the difference between repayment and interest-only?
With a repayment mortgage, each monthly payment covers the interest and part of the loan, so you owe nothing at the end of the term. With interest-only, you pay just the interest. Payments are lower, but you still owe the full loan at the end and need a plan to repay it.
Does a longer mortgage term save money?
A longer term lowers your monthly payment but means paying interest for longer, so the total cost goes up. Overpaying when you can, within your lender's limits (often 10% a year), shortens the term and cuts the interest.
How accurate is this mortgage calculator?
It uses the standard formula lenders use for a fixed interest rate over the whole term. In reality most UK mortgages switch to a different rate when a fixed or tracker deal ends, and some add fees to the loan, so treat the result as a guide.
Last checked 5 October 2026.