Mortgage calculator and repayment schedule
Two tools in one. The first tab works out your monthly payment for a repayment, interest only or part and part mortgage, and shows what it would be if rates were higher. The second shows how the loan is paid off year by year, how much of each payment goes on interest, what happens when an initial rate ends, and how much sooner you could be mortgage free by overpaying.
Mortgage calculator
Work out your monthly payment, then see how the loan is paid off year by year and what overpaying would do. Nothing you enter is stored.
Your mortgage
The cost over the term
Of your first payment, £750.00 is interest and £361.66 pays off the loan.
If rates were higher
A quick check on whether the payment would still be comfortable.
Estimates only, not mortgage advice. Interest is worked out monthly at the annual rate divided by 12; lenders vary, so your actual payment may differ slightly. Fees, insurance and product changes are not included.
Who this calculator is for
First time buyers checking what they can afford, homeowners coming to the end of a fixed rate, and anyone wondering whether overpaying their mortgage is worth it. For an existing mortgage, enter the balance you owe now and the time left.
The 2026/27 rules it uses
- Repayment payments use the standard mortgage formula, with interest worked out monthly at the annual rate divided by 12.
- When an initial rate ends, the payment is recalculated on the balance then owed over the rest of the term.
- Interest only borrowing pays the interest each month; the capital is owed in full at the end of the term.
- Overpayments and lump sums reduce the balance, and the monthly payment stays the same, so the mortgage finishes sooner.
- Most lenders allow overpayments of up to about 10% of the balance a year during an initial deal without an early repayment charge. The calculator flags years that go over.
Frequently asked questions
Why does so little of my payment reduce the loan at first?
Interest is charged on what you still owe, which is highest at the start. As the balance falls, less of each payment goes on interest and more pays off the loan.
Is it worth overpaying my mortgage?
Every pound overpaid saves interest at your mortgage rate, and the calculator shows how much sooner you would be mortgage free. It is worth weighing against keeping an emergency fund, paying off more expensive debts first, and pension contributions, which can come with tax relief.
What happens when my fixed rate ends?
Unless you switch to a new deal, most lenders move you onto their standard variable rate, which is usually higher. Choose an initial rate followed by a different rate to see how your payment would change.
Read more on this
Estimates only, not mortgage advice. Lenders calculate interest differently and fees are not included, so your actual payments may differ. If you are choosing or changing a mortgage, speak to a qualified mortgage adviser.