Is overpaying your mortgage worth it?
Usually, yes, if you have no expensive debts and a cash buffer. On a £200,000 mortgage at 4.5% over 25 years, an extra £100 a month saves about £21,142 in interest and clears the loan 3 years 6 months early.
What regular overpayments save.
| Extra a month | New payment | Paid off in | Total interest | Interest saved | Time saved |
|---|---|---|---|---|---|
| £50 | £1,161.66 | 23 years 2 months | £121,965 | £11,534 | 1 year 10 months |
| £100 | £1,211.66 | 21 years 6 months | £112,358 | £21,142 | 3 years 6 months |
| £200 | £1,311.66 | 18 years 11 months | £97,219 | £36,280 | 6 years 1 month |
| £300 | £1,411.66 | 16 years 11 months | £85,792 | £47,708 | 8 years 1 month |
| £500 | £1,611.66 | 14 years | £69,613 | £63,887 | 11 years |
Assumes the rate stays at 4.5% for the whole term and the overpayment starts from month one. In real life your rate will change when deals end, but the pattern holds: money paid early saves interest for every remaining year.
What about a one-off payment?
Most lenders let you overpay up to 10% of the balance each year without a charge during a fixed or tracker deal. Go above that and you may pay an early repayment charge (ERC), often 1–5% of the excess. Check your mortgage offer, or wait until your deal ends, when overpayments are usually unlimited.
When you overpay, many lenders ask whether you want to shorten the term or lower the monthly payment. Shortening the term saves the most interest; lowering the payment gives you more breathing room each month.
Compare it with what your savings earn after tax.
Overpaying a 4.5% mortgage is like earning a guaranteed, tax-free 4.5% return. To beat it, a savings account would need to pay more than this after tax:
| Your situation | Savings rate needed to beat overpaying |
|---|---|
| Interest still within your Personal Savings Allowance, or in an ISA | 4.5% |
| Basic-rate taxpayer, allowance used up (20% tax) | 5.63% |
| Higher-rate taxpayer, allowance used up (40% tax) | 7.50% |
The Personal Savings Allowance lets basic-rate taxpayers earn £1,000 of interest a year tax-free, and higher-rate taxpayers £500. Interest inside an ISA is always tax-free.
Do these first.
- Clear expensive debt. A credit card at 24.9% APR costs far more than a 4.5% mortgage. Every £100 there saves much more.
- Build an emergency fund. Money paid into a mortgage is hard to get back. Keep 3–6 months of essential costs in easy-access savings. See how much to keep.
- Take any free pension money. If your employer matches extra contributions, that match usually beats overpaying.
- Check the ERC. Stay within the 10% allowance unless the saving clearly outweighs the charge.
Enter your balance, rate and overpayment in the mortgage calculator to see your exact interest and time saved.
Mortgage overpayment FAQs
Is it better to overpay monthly or in a lump sum?
The earlier money goes in, the more it saves. A regular monthly overpayment from today usually saves more than saving up and paying a lump sum later, as long as you stay within your lender's limit.
Does overpaying reduce my monthly payment?
Only if you ask the lender to recalculate. Otherwise most lenders keep the payment the same and the mortgage simply ends sooner.
Does overpaying help when I remortgage?
Yes. A lower balance means a lower loan-to-value, which can qualify you for better rates at your next deal.
Can I get overpayments back?
Some flexible mortgages let you borrow back overpayments, but most do not. Treat overpaid money as locked away.
MoneyHelper: overpaying your mortgage · GOV.UK Personal Savings Allowance. Figures are worked examples for planning, not financial advice.