Mortgage Overpayment Calculator UK — See How Extra Payments Save You Thousands
Calculate how much you can save by making regular or lump-sum overpayments on your UK mortgage. See how many years you can cut from your mortgage term.
Making even small overpayments on your UK mortgage can save thousands in interest and cut years off your mortgage term. Most UK mortgage lenders allow overpayments of up to 10% of the outstanding balance per year without early repayment charges. A monthly overpayment of just £200 on a £250000 mortgage at 4.5% saves approximately £35000 in interest and clears the mortgage 6 years early.
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Key Information
| Parameter | Details |
|---|---|
| Typical Overpayment Allowance | 10% of balance per year (no penalty) |
| £200/month Overpayment Savings | ~£35,000 interest saved on £250K |
| Years Saved with £200/month | Approximately 6 years on 25-year term |
| Annual Lump Sum Impact | £5,000/year saves ~£40,000 total |
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Use Calculator NowFrequently Asked Questions
How much should I overpay on my mortgage?
Start with whatever you can comfortably afford even £50/month makes a difference. On a £200000 mortgage at 4.5%: £50/month overpayment saves £12000 and 2 years. £100/month saves £22000 and 4 years. £200/month saves £35000 and 6 years. Always ensure you have a 3-6 month emergency fund before committing to regular overpayments as you may not be able to get the money back.
Should I overpay mortgage or invest in ISA?
With mortgage rates at 4-5% and stock market historical returns of 7-10% investing in a Stocks and Shares ISA mathematically beats overpaying on average. However mortgage overpayment is a guaranteed return at your interest rate with zero risk. Many financial advisors recommend doing both: overpay mortgage by a comfortable amount and invest the rest in ISA for long-term growth and tax-free returns.
Can I get mortgage overpayments back?
It depends on your lender. Some offer an overpayment reserve or borrow-back facility allowing you to reclaim overpayments. Most do not meaning once overpaid the money is locked in your property equity. Offset mortgages link your savings to your mortgage reducing interest while keeping savings accessible. Consider an offset mortgage if you want the benefits of overpaying with the flexibility of access.
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Last updated: 24 March 2026