Overpaying your mortgage is one of the simplest ways to become debt-free sooner. Every extra pound goes straight off the balance, so you pay interest on less money for every month that follows. Even small, regular overpayments add up to years off your term.
This guide explains how overpayments work in the UK, what they could save you, the rules your lender will set, and when you'd be better off doing something else with the money.
How much could overpaying save?
Take a typical repayment mortgage: £200,000 over 25 years at 4.5%. The normal monthly payment is about £1,112, and you'd pay around £133,500 in interest over the full term.
Here's what a regular monthly overpayment does to that, assuming the rate stays at 4.5%:
| Extra each month | Mortgage paid off | Interest saved |
|---|---|---|
| £50 | 1 year 10 months sooner | about £11,500 |
| £100 | 3 years 6 months sooner | about £21,100 |
| £200 | 6 years 1 month sooner | about £36,300 |
| £300 | 8 years 1 month sooner | about £47,700 |
A one-off lump sum helps too. Paying £5,000 off at the start of the same mortgage saves about £10,000 in interest and finishes it 1 year 1 month early.
Overpayments made early in the mortgage save the most, because that's when the balance, and so the interest, is highest.
Try your own numbers in the free mortgage payoff calculator to see your new payoff date and interest saved.
Check your lender's overpayment rules first
The 10% allowance
Most UK lenders let you overpay up to 10% of your outstanding balance each year without a penalty. On a £200,000 balance that's £20,000 a year, so most regular overpayments sit comfortably inside it. Some lenders set a different limit, so check your mortgage offer or ask your lender.
Early repayment charges
If you go over the allowance while you're on a fixed or tracker deal, you'll usually pay an early repayment charge (ERC), often between 1% and 5% of the amount over the limit. ERCs normally end when your deal ends, so the months after a deal finishes, or when you move to your lender's standard variable rate, are often the cheapest time to make a big overpayment.
Reduce your term or your payment?
When you overpay, lenders handle it in one of two ways:
- Reduce the term: your monthly payment stays the same and the mortgage ends sooner. This saves the most interest.
- Reduce the payment: the end date stays the same and your monthly payment drops. This gives you breathing room but saves less.
Some lenders do one automatically, so tell them which you want when you overpay.
Ways to overpay
- A regular monthly overpayment: set up a standing order for a fixed extra amount. It's the easiest habit to keep.
- Lump sums: a bonus, tax refund or inheritance can go straight onto the balance.
- Keep your old payment after remortgaging: if a new deal lowers your monthly payment, keep paying the old amount and treat the difference as an overpayment.
- Round up: rounding £1,112 up to £1,200 is an £88 overpayment you'll barely notice.
When overpaying isn't the best move
Your mortgage is usually your cheapest debt. Before overpaying, check these first:
- Clear more expensive debt first. Credit cards, overdrafts and personal loans almost always charge more than a mortgage. Every pound there saves you more. The debt payoff calculator can help you plan it.
- Build an emergency fund. Money paid off your mortgage is hard to get back. Aim for a few months of essential spending in easy-access savings first.
- Compare with savings rates. If you can earn more in a tax-free savings account than your mortgage rate costs, saving may come out ahead. Many people overpay anyway for the certainty and peace of mind.
- Don't miss out on your employer's pension contributions. If your employer matches pension contributions, paying in enough to get the full match is usually worth more than overpaying.
A simple plan
- Find your current balance, interest rate, deal end date and overpayment allowance on your latest mortgage statement.
- Pay off higher-interest debt and set aside an emergency fund.
- Use the mortgage payoff calculator to pick an overpayment you can afford every month.
- Set up a standing order, and ask your lender to reduce your term.
- Review it each year, and when your deal ends, before you remortgage.
Examples assume a fixed 4.5% interest rate for the whole term and overpayments that stay within the lender's allowance. Your figures will depend on your own mortgage. This guide is general information, not financial advice.