Mortgage calculator UK: repayments and overpayments
Work out your monthly payment, see what overpaying saves and test a rate rise, all in your browser with nothing sent anywhere.
Your mortgage
Your result
Figures are illustrations, not a mortgage offer or advice. Speak to an FCA-authorised broker or lender before deciding.
Balance over time
Year-by-year table
If your rate rises
Monthly payment at your rate and at 1, 2 and 3 percentage points higher, on the same loan and term, before any overpayment.
How much can I borrow?
This is a rough illustration using 4.5 times income. Lenders set their own limits and also look at spending, debts, credit history and deposit, so the amount a lender would offer can be higher or lower.
How this mortgage calculator works
This mortgage calculator UK borrowers can use for free works from three things you type in: the amount borrowed, the interest rate and the term in years. It then runs the numbers month by month, the way a repayment mortgage does.
On a repayment mortgage the monthly payment stays fixed for the term at the rate you entered. Each month the interest on the outstanding balance is paid first and the rest of the payment reduces the balance. The formula is payment = balance × r ÷ (1 − (1 + r)^−n), where r is the monthly rate (the annual rate divided by 12) and n is the number of monthly payments.
An interest-only mortgage works differently. You pay only the monthly interest, so the balance stays the same unless you repay some of it. The full amount is still owed at the end of the term.
How overpaying works
An overpayment comes straight off the balance, so every later month charges less interest. As a mortgage overpayment calculator, it runs the schedule twice, with and without your overpayment, then compares the two to show the years saved and the interest saved. A lump sum is applied after the number of years you choose. Check your own mortgage terms, because some deals limit or charge for overpayments.
What else you get
- Rate shock: the monthly payment at your rate plus 1, 2 and 3 percentage points, on the same loan and term.
- Affordability: for the “how much can I borrow” question, your income multiplied by 4.5, one commonly quoted illustration. Lenders set their own limits and also look at spending, debts and credit history.
- Chart and table: the balance falling year by year, with and without overpayments.
No lender rates are built in. The starting 5% is only an example, so replace it with the rate from your own illustration. Results leave out fees, insurance and any change of rate during the term.
Mortgage calculator questions
How much can I borrow for a mortgage?
A common illustration is about 4.5 times your annual income, which the calculator works out for you. Lenders set their own limits and also look at your spending, debts, credit history and deposit. The amount a lender offers can be higher or lower, so treat this as a rough guide only.
What happens if I overpay my mortgage?
An overpayment reduces the balance, so less interest is charged from then on. Depending on how the lender applies it, the result can be a shorter term or lower payments. The calculator shows the shorter-term effect. Many deals limit overpayments or charge for going over the limit, so read your terms first.
What is the difference between repayment and interest-only?
With a repayment mortgage each payment covers interest and some of the loan, so the balance reaches zero by the end of the term. With interest-only you pay just the interest, so the amount borrowed is still owed at the end. Lenders have their own rules on when interest-only is available.
How much more would my payments be if rates rise?
The rate shock table shows your monthly payment at your rate plus 1, 2 and 3 percentage points, on the same loan and term. The last column is the extra monthly cost compared with your current rate. In real life a rise applies to the balance left at that point, so the figures are an approximation.
Is this mortgage calculator a mortgage offer?
No. It gives illustrations only, based on the numbers you type, and it does not include fees, insurance or lender-specific rules. Speak to an FCA-authorised broker or lender for figures based on your circumstances.