Mortgage repayment calculator
Repaying a £220,000 mortgage at 4.50% over 25 years gives an estimated monthly payment of £1,222.83, with total interest of about £146,849 across the term, under the mortgage regulation the Financial Conduct Authority sets out on gov.uk. The exact figures always depend on the rate and term entered.
Monthly mortgage repayments depend on the amount borrowed, the interest rate and the term. Borrowing £200,000 at 4.5% over 25 years gives an estimated monthly payment of £1,112. Over the full term that is approximately £333,600, of which £133,600 is interest. A shorter term raises the monthly figure but reduces total interest paid. Enter your own figures below for an exact calculation.
How is the monthly payment worked out?
A repayment mortgage is designed to reach zero at the end of the term. Each month the lender charges interest on the balance still outstanding, and the fixed payment covers that interest plus a slice of capital. In the early years the balance is high, so most of the payment is interest and the balance falls slowly. As the balance drops the interest shrinks and more of each payment reduces the capital, which is why the loan clears faster towards the end of the term.
Two levers move the total cost. A lower rate cuts the interest directly. A shorter term raises the monthly payments but ends the interest sooner, which is estimated to save a substantial amount over the life of the loan.
What would this example cost overall?
Borrowing £220,000 at 4.50% over 25 years gives an estimated monthly payment of £1,222.83. Across the 25 years that adds up to an estimated £366,849, of which £146,849 is interest. A 20-year term instead is estimated to raise the monthly payment but lower the total interest, because the debt is cleared five years sooner.
Common questions
How is the monthly payment worked out?
It uses the standard repayment formula. Each month you pay interest on the balance left, plus enough capital that the loan clears exactly at the end of the term. Early on most of the payment is interest; later most is capital. The monthly figure stays level if the rate does not change.
Why is the total interest so high?
Because interest is charged on the outstanding balance every month for the whole term. On the £220,000 example at 4.50% over 25 years you repay £146,849 in interest, on top of the amount borrowed. A shorter term or a lower rate cuts that sharply.
What is the difference between repayment and interest-only?
A repayment mortgage clears the loan by the end of the term because each payment includes capital. An interest-only mortgage pays only the interest, so the monthly cost is lower but the full balance is still owed at the end. This tool models a repayment mortgage.
Does a longer term make it cheaper?
Only month to month. Stretching the term lowers each payment but you pay interest for more years, so the total cost rises. Shortening the term does the opposite: higher monthly payments but far less interest overall.
Is the rate here fixed for the whole term?
The calculation assumes one rate for the full term, which gives a clean comparison. In practice you usually fix for two to five years and then remortgage, so the real payment changes whenever your rate does.
What would this example cost overall?
Borrowing £220,000 at 4.50% over 25 years gives an estimated monthly payment of £1,222.83. Across the full 25 years that comes to an estimated £366,849 in total, of which £146,849 is interest rather than capital. Shortening the term raises the monthly figure but lowers the total interest, because the loan clears sooner.
Sources & Rate Verification
Rates verified against official statutory guidance on 6 September 2026.