Whether to overpay or save comes down to three things: rates, tax, and access. If your mortgage rate beats your after-tax savings rate AND you already have an emergency fund, overpaying usually wins. If you don't have cash savings yet, save first.
You'll be mortgage-free 6 years 9 months earlier
and save £46,940 in interest.
| Without | With overpay | |
|---|---|---|
| Term | 25 years | 18 years 3 months |
| Total interest | £156,277 | £109,338 |
| You save | £46,940 · 6y 9m |
A lower interest rate could save you thousands more on top. See if you could remortgage to a better deal.
We may receive a commission if you remortgage through a partner broker. This never affects the rate you're offered.
Basic-rate taxpayer earning 4% gross on an easy-access account effectively gets ~3.2% after tax (assuming Personal Savings Allowance is used). Higher-rate taxpayer gets ~2.4% after tax.
If your mortgage is at 4.5%+, overpaying beats both. If it's a sub-2% legacy fix, savings probably win.
Money in savings is yours to spend instantly. Money paid onto a mortgage is locked into your home — you can only get it back by remortgaging (with fees and credit checks) or selling.
Always keep 3–6 months of essential outgoings in easy-access cash before overpaying. After that, the maths favours overpaying for most UK homeowners.
A cash ISA pays interest tax-free — compare its rate directly to your mortgage rate (no tax adjustment needed). A stocks-and-shares ISA has higher expected long-term returns but with risk. Many people split: overpay to the 10% cap, ISA the rest.
Important: This article is for general information and is not financial advice. Always speak to a qualified UK mortgage adviser before making decisions about overpayments, remortgaging, or your specific mortgage product.