Enter your outstanding balance, interest rate, remaining term and monthly overpayment to see exactly how much interest you save and how many months earlier you pay off your mortgage. Free UK mortgage overpayment calculator, no registration, results in seconds.
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Four figures is all it takes. This free mortgage overpayment calculator UK tool does the rest. Here is where to find them.
This is how much you still owe on your mortgage, not the original loan amount. Find it on your most recent mortgage statement, your lender's online portal, or by calling your lender. Use the current balance, not the balance from when you took the mortgage out.
Enter your current rate as a percentage. If you are on a fixed rate, this is on your mortgage offer letter. If you are on a tracker or variable rate, check your lender's current rate. Use the rate you are actually paying now, not the rate when you originally applied.
Enter how many years are left on your mortgage. If your mortgage has 18 years and 6 months remaining, enter 18 (the calculator works in full years). Your remaining term is shown on your mortgage statement or annual summary.
Enter how much extra you are thinking of paying each month. This is on top of your required monthly payment, not instead of it. Start with a figure you are confident you can sustain. The calculator also lets you add a one-off lump sum to see the combined effect.
The calculator holds your current rate constant for the full remaining term. In reality you will likely remortgage to a different rate at some point, which changes the numbers. The results are a guide to the order of magnitude of the saving, not a guaranteed figure. Your actual savings will vary.
Before you start overpaying, check your allowance. Most fixed rate mortgages cap overpayments at 10% of the outstanding balance per year without an early repayment charge. Go above that limit during the fixed period and you pay a charge, typically 1% to 5% of the excess amount, which can wipe out part of the interest saving.
| Mortgage type | Typical overpayment allowance | ERC if exceeded? |
|---|---|---|
| Fixed rate (during deal) | Up to 10% of outstanding balance per year | Yes: 1% to 5% of excess |
| Fixed rate (after deal ends) | Unlimited | No ERC |
| Tracker mortgage | Usually unlimited | Usually no ERC |
| Standard variable rate | Usually unlimited | Usually no ERC |
| Offset mortgage | Flexible | Usually no ERC |
Allowances vary by lender and product. Always confirm your specific overpayment limit with your lender before making a large overpayment.
If you are on a tracker or variable rate mortgage, you can usually overpay as much as you like without any penalty. This makes trackers particularly good for overpayers. If you are remortgaging and plan to overpay significantly, a tracker or a fixed rate with a high overpayment allowance may be worth comparing against a lower standard fixed rate.
The maths behind mortgage overpayments is more powerful than most people expect.
Every pound you overpay reduces your outstanding balance immediately. Because mortgage interest is calculated on the outstanding balance, a smaller balance means less interest charged next month. That means more of your regular monthly payment chips away at the capital rather than going to interest. Which reduces the balance further. Which reduces interest further. The saving compounds over the full remaining term.
Use this as a pay off mortgage early calculator to see exactly how many months come off your term. A £200 overpayment on a £200,000 mortgage at 4.5% with 25 years remaining does not just save £200 in interest. It saves several thousand pounds over the life of the mortgage and cuts the term by years. The earlier in the mortgage term you start, the greater the effect, because you are removing a pound of balance that would otherwise have been generating interest for 20-plus years.
The earlier you start overpaying, the more it saves. A £200 overpayment in year one saves significantly more than the same £200 in year fifteen. The calculator shows you the difference.
Sometimes a lower rate through remortgaging saves more than overpaying at a higher rate. Woodhall Mortgages compares the whole market and can advise on whether your money works harder through overpayments, a remortgage, or both.
Get Mortgage AdviceThe calculator shows what overpaying saves at your current rate. But if a remortgage could get you a lower rate, the combined saving can be significantly higher. Woodhall Mortgages compares the whole market and advises on which approach works hardest for your money.
Initial discussion free. A broker fee of £299 is payable if you choose to proceed following a formal mortgage offer. This fee is non-refundable once charged. We may also receive commission from the lender. Your home may be repossessed if you do not keep up repayments on your mortgage.
Get Mortgage AdviceWoodhall Mortgages is authorised and regulated by the Financial Conduct Authority (FRN 762513). As a whole-of-market mortgage broker, we consider mortgages from across the market, subject to lender criteria and product availability. Calculator results are illustrative estimates only and do not constitute regulated financial advice. Actual savings depend on your specific mortgage terms, lender and any rate changes. Always confirm your overpayment allowance with your lender before making large payments. Your home may be repossessed if you do not keep up repayments on your mortgage.
Buying a home or reviewing your mortgage can feel complicated, but it doesn’t have to be. A quick conversation can give you clarity on your options, your budget, and the next realistic steps. There is no obligation and no pressure, just straightforward guidance tailored to you. Complete the short form below and we will be in touch to help you move forward with confidence.
