Mortgage Overpayment Calculator
See how much interest you could save, and how much sooner you could be mortgage-free, by paying a little extra.
Your mortgage today
Your overpayment
Use either or both. We assume your monthly payment stays the same and the extra shortens your term.
How your balance comes down
Want a real figure, not an estimate?
Calculators give you a rough idea. Leave your name and number and a CeMAP-qualified advisor will call to talk you through your numbers and what lenders would actually offer.



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How overpaying your mortgage works
An overpayment is anything you pay on top of your normal monthly payment. It goes straight off the amount you owe, so less interest is charged on it from then on. Even small, regular amounts can take years off a mortgage.
Monthly overpayments or a lump sum?
A monthly overpayment is a set amount on top of your usual payment, such as £100 a month. A lump sum is a one-off payment, perhaps from savings, a bonus or an inheritance. You can use either or both in the calculator above.
Shorter term or lower payments?
This calculator assumes you keep paying the same amount each month, so overpaying shortens your mortgage. Some lenders will instead lower your monthly payment and keep the same end date. Ask your lender which they do, and whether you can choose.
Check your overpayment allowance
Most fixed and discounted deals let you overpay up to 10% of your balance each year without a charge. Go over that and you may pay an early repayment charge. The limit and how it is worked out vary between lenders, so check your mortgage offer or ask your lender before you pay.
Is overpaying right for you?
Overpaying usually makes most sense once you have savings put aside for emergencies and no more expensive debts, such as credit cards or loans. Money you overpay is not easy to get back, so keep enough in reserve.
If your deal is ending soon, it can be worth reviewing your mortgage at the same time. Request a quote or call us on 01202 733 809.
Next step: Our guide to remortgaging