See how regular overpayments — or a one-off lump sum — cut years off the mortgage and slash the interest.
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yrs
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25 yrs
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Switch to “Shorten the term” to model regular overpayments.
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Interest saved
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over the life of the mortgage
Mortgage-free sooner
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New payoff time
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New monthly payment
£0
With vs without overpaying
Balance over time
Should you overpay? Weigh it up
In favour
A guaranteed, tax-free return equal to your mortgage rate — no savings account or investment can promise that.
Protection if rates rise. Rates are hard to predict: the Bank of England base rate sat at just 0.1% in 2021 yet reached 5.25% by 2023, and the cheapest fixes went from under 2% to above 6% in barely two years. A smaller balance softens the blow at your next renewal.
Peace of mind. Less debt, lower payments when you remortgage, and being mortgage-free sooner — worth a lot to many people even when the spreadsheet is close.
Things to weigh
Investing can win. When your money reliably earns more than your mortgage rate — say a tax-free ISA returning 6–7% against a 4–5% mortgage — investing the same cash usually leaves you better off over the long run.
The money is locked away. Overpayments disappear into the house and can't easily be retrieved in an emergency, unlike savings or an ISA.
Mind the allowance and the basics. Going beyond your lender's yearly limit (often 10%) can trigger an early repayment charge during a fix — and it's usually wise to clear pricier debt and hold an emergency fund first.
Models your initial rate for the fixed period, then the revert rate for the rest of the term. Shorten the term keeps your payment and clears the mortgage sooner; Lower the payment uses a lump sum to reduce the balance and re-spread it over the same term. Many lenders cap penalty-free overpayments at 10% of the balance a year — check your deal.