Mortgage Repayment Calculator
Enter your mortgage details to see your monthly payment, how much interest you will pay, and how your balance falls year by year.
Your mortgage details
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Your results will appear here
Enter your property value, balance, interest rate and term, then press Calculate to see your monthly payment and a year-by-year breakdown.
How mortgage repayments are calculated
With a repayment mortgage (also called a capital and interest mortgage), you pay the same amount every month. Each payment covers that month's interest, and whatever is left over reduces the amount you owe. By the end of the term, the balance reaches zero.
M = P × r(1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)
Because interest is charged on the balance you still owe, the early payments are mostly interest. As the balance falls, less of each payment goes on interest and more goes towards clearing the loan. You can see this shift in the “Where your payments go” chart once you calculate.
Worked example
Say you borrow £200,000 over 25 years at an interest rate of 5%, on a property worth £250,000.
- Your monthly payment would be £1,169.18.
- In the first year you would pay £9,906.35 in interest but only reduce the balance by £4,123.81.
- Over the full term you would pay £150,754.02 in interest.
- Stretching the term to 35 years would lower the payment to £1,009.38 a month, but the total interest would rise to £223,937.65.
Open this example in the calculator to see the full year-by-year breakdown.
Understanding your results
- Monthly payment: what you would pay each month to clear the mortgage by the end of the term.
- Total interest: everything you would pay on top of the amount borrowed.
- Total repayable: the balance plus all the interest, which is the full cost of the loan.
- Loan to value (LTV): your balance as a percentage of the property's value. Lenders usually offer better rates at lower LTVs, so it's worth checking as your balance falls or your property's value changes.
Frequently asked questions
Does this include fees, insurance or other costs?
No. The calculator covers the loan itself: the amount borrowed and the interest on it. Arrangement fees, insurance, and any other charges are not included.
Does it work for interest-only mortgages?
No. It assumes a repayment mortgage, where every payment includes some of the balance. With an interest-only mortgage your monthly payment would only cover the interest, and the full balance would still be owed at the end of the term.
What happens if my interest rate changes?
The calculator assumes the rate stays the same for the whole term. If you are on a fixed deal that ends, or a variable rate, enter your balance remaining and the new rate to see how your payments would change.
Should I choose a longer or a shorter term?
A longer term lowers your monthly payment but means paying interest for longer, so the total cost is higher. A shorter term costs more each month but less overall. The worked example above shows the difference for a typical mortgage.
How accurate are the results?
They are estimates for illustration. Lenders may calculate interest slightly differently (for example daily rather than monthly), so your actual payments can differ a little. Speak to your lender or a qualified mortgage adviser before making decisions.