What an overpayment changes
An overpayment reduces the outstanding balance sooner. In this estimate, that can shorten the projected term and reduce the interest charged over the remaining schedule.
Calculator
Mortgage overpayment calculator UK
Estimate how long it takes to clear your mortgage with regular overpayments, then export the full timeline when you’re ready.
Your details
Enter the mortgage balance, interest rate, and current monthly payment, then test an overpayment.
Results
See your payoff timeline
Run the plan to see the projected payoff date, interest impact, and full amortisation schedule.
Your mortgage results will appear here
Add your mortgage details and run the calculator.
How it works
Understanding mortgage overpayment estimates
Check your mortgage terms
Lenders can apply overpayments in different ways. Check your agreement for annual allowances, early repayment charges, payment recalculation rules, and whether the rate can change during the term.
- Regular overpayment: A recurring extra amount added to each monthly payment.
- Lump sum: A one-off payment that may be subject to a separate allowance.
- Rate changes: A future rate change can make the projection differ from your statement.
Use the timeline as a planning reference
Try a few realistic overpayment amounts, then compare the projected dates and total interest. Confirm the final figures with your lender before making a change to your mortgage payment.
Guide
Mortgage overpayments, explained for UK homeowners
How overpaying works, how much you can overpay without a charge, a worked example in pounds, and whether to overpay, save or clear other debts first.
How mortgage overpayments work
An overpayment is anything you pay on top of your normal monthly mortgage payment. It goes straight off the balance, so less interest is charged every month after that. Over a long mortgage, even a small regular overpayment can take years off the term.
- Regular overpayments: a fixed extra amount every month, often set up as a separate standing order.
- Lump sums: a one-off payment, for example from a bonus or savings. These usually count towards the same yearly allowance.
- Shorter term or lower payment: after an overpayment, some lenders lower your monthly payment rather than the term. If you want to be mortgage-free sooner, ask your lender to keep the payment the same.
How much can you overpay?
Many lenders let you overpay up to 10% of the balance each year without an early repayment charge. On a £200,000 mortgage that is £20,000 a year. Pay more than the allowance during a fixed or discounted deal and the lender can charge a percentage of the extra, so check your mortgage offer first. Flexible and offset mortgages often let you overpay and take the money back later.
Worked example: overpaying a £200,000 mortgage
Take a £200,000 repayment mortgage over 25 years at 4.60%, the Bank of England's average rate on new mortgages in August 2026. The monthly payment is £1,123.05, and over the full term you would pay about £136,914 in interest.
| Overpayment | Mortgage-free in | Time saved | Interest saved |
|---|---|---|---|
| £100 a month | 21 years 6 months | 3 years 6 months | £21,794 |
| £200 a month | 18 years 11 months | 6 years 1 month | £37,364 |
| £500 a month | 14 years | 11 years | £65,694 |
- An extra £100 a month clears the mortgage 3 years 6 months sooner and saves about £21,794 of interest.
- £200 a month saves 6 years 1 month and about £37,364.
- £500 a month, 3% of the balance a year and well inside a 10% allowance, takes 11 years off and saves about £65,694.
How to pay off your mortgage in 10, 15 or 20 years
To clear the same £200,000 sooner, this is the monthly payment you would need, and how much more that is than the 25-year payment of £1,123.05:
| Pay off in | Monthly payment | Extra each month | Total interest |
|---|---|---|---|
| 10 years | £2,082.42 | £959.37 | £49,891 |
| 15 years | £1,540.23 | £417.18 | £77,241 |
| 20 years | £1,276.12 | £153.07 | £106,269 |
Use the calculator above with your own balance, rate and payment to find the overpayment that gets you to your target date.
Overpay, save or clear other debts first?
- Clear expensive debts first. Credit cards average 21.55% against about 4.60% on a new mortgage, so a pound off a card saves far more interest. Use the debt snowball calculator to plan them, and see what credit card minimum payments really cost.
- Keep some savings in reserve. Have enough to cover at least three months of spending before you overpay, because money paid into a standard mortgage is hard to get back.
- Compare your savings rate. If your savings earn more after tax than your mortgage costs, saving can come out ahead. If not, overpaying usually wins.
- Check your deal. Look up your overpayment allowance and any early repayment charges before you start.
Sources
Mortgage overpayment FAQs
Is it better to overpay my mortgage or reduce the term?
Overpaying each month and shortening the term have the same effect on interest: both clear the balance sooner. The difference is flexibility. A regular overpayment can usually be stopped at any time, while a shorter term raises the payment you are committed to.
When you overpay, ask your lender whether it will reduce your monthly payment or the remaining term. If you want to be mortgage-free sooner, ask it to keep the payment the same and shorten the term.
How much can I overpay without a penalty?
Many lenders let you overpay up to 10% of the balance each year without an early repayment charge. On a £200,000 mortgage that is £20,000 a year. Above the allowance, a fixed or discounted deal usually charges a percentage of the extra paid, so check your mortgage offer or ask your lender before paying more.
How can I pay off my mortgage in 10 years?
Work out the monthly payment that clears the balance in 10 years and pay the difference as an overpayment. In our example, £200,000 at 4.60% needs £2,082.42 a month for 10 years, which is £959.37 more than the 25-year payment. Put your own balance and rate into the calculator above and try overpayments until the payoff date lands where you want it.
Should I clear my credit cards before overpaying my mortgage?
Usually, yes. Credit cards cost far more than a mortgage: the Bank of England's average rate on interest-charging cards is 21.55%, against about 4.60% on new mortgages. Every pound that clears a card saves more interest than a pound off your mortgage. The debt snowball calculator shows the order to clear them in.
Is it better to overpay my mortgage or save?
Compare the interest on your mortgage with what your savings earn after tax. If your mortgage rate is higher, overpaying usually saves more than saving earns. Keep enough savings to cover at least three months of spending first, because money paid into a standard mortgage can be hard to get back.