Mortgage Calculators
Mortgage Overpayment Calculator
Overpaying is the highest-return thing most homeowners can do with spare money. See exactly what it buys you before you commit to it.
- Years cut off your term
- Total interest saved
- When the mortgage would be cleared
- What your lender is likely to allow
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Most lenders allow overpayments of up to ten per cent of the balance each year without penalty during a fixed period. Check your own offer before setting up a standing order. This is an estimate based on typical lender criteria and current rates. It is not advice, a recommendation, or an offer of credit. What you can actually borrow depends on your circumstances and the lender's own assessment.
Why overpaying early is worth so much more
Interest is charged on the balance outstanding, so every pound you take off the balance stops earning the lender interest for the whole remaining term. An overpayment in year two of a 25 year mortgage avoids 23 years of interest on that amount. The same overpayment in year twenty avoids five.
Most lenders allow you to overpay up to ten per cent of the balance each year without an early repayment charge. Go beyond that during a fixed period and the charge can easily wipe out the saving, so check your own terms before setting up a standing order.
Overpaying is not automatically the right call. If you have credit card or unsecured debt at a higher rate, clearing that first returns more. If you have no emergency fund, money in the mortgage is money you cannot easily get back.
What £200 a month is actually worth
On a £200,000 mortgage at 4.5% over 25 years, the contractual payment is about £1,112 and the total interest across the term is roughly £133,000. Add £200 a month from the start and the mortgage clears in a little under 20 years instead of 25, and the total interest falls to around £103,000. That is roughly £30,000 saved and five years of payments avoided, for £200 a month.
Timing changes the answer dramatically. The same £200 a month started in year fifteen rather than year one saves a small fraction of that, because there is far less balance left for it to work on and far less term left for the saving to compound. Overpayments are worth the most at exactly the point in life when they are hardest to afford, which is an uncomfortable but useful thing to know.
A one-off lump sum behaves the same way. £10,000 paid off that same mortgage in year two saves roughly £12,000 of interest over the term. The same £10,000 in year twenty saves closer to £1,000.
When overpaying is the wrong move
If you are carrying credit card debt at 20% or more, or a car finance agreement in the teens, clearing those first returns considerably more than overpaying a mortgage at 4 or 5%. The arithmetic is not close. Overpaying the mortgage while revolving a credit card balance is a common and expensive mistake.
If you have no accessible savings, money in the mortgage is money you cannot reach. Releasing it later means a further advance or a remortgage, both of which involve an application, an affordability assessment and a credit check. Most advisers would want to see three to six months of essential outgoings held somewhere accessible before any voluntary overpayment starts.
And check the early repayment charge before you set up a standing order. Exceeding the annual allowance during a fixed period can trigger a charge that wipes out several years of saving in one go. The allowance is set out in your mortgage offer, and lenders will confirm your remaining allowance on request.
Where to go next
Independent sources
- MoneyHelper on repaying early — An impartial view on whether overpaying is right for you
- MoneyHelper mortgage calculators — A second opinion on the same figures
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Frequently Asked Questions – Mortgage Overpayment Calculator
How much can I overpay on my mortgage?
Most lenders allow up to ten per cent of the outstanding balance each year without penalty during a fixed or discounted period. Some are more generous, a few less. Once you are on a standard variable rate there is usually no limit at all.
Does overpaying reduce the term or the payment?
That is your choice, and it is worth being deliberate. Reducing the term keeps the payment the same and clears the mortgage sooner, which saves the most interest. Reducing the payment gives you monthly breathing room but saves considerably less.
Is it better to overpay or save the money?
Compare the mortgage rate with the interest you would earn after tax. If the mortgage rate is higher, overpaying usually wins. But keep an accessible emergency fund first, because money paid into a mortgage is difficult to get back out.
Will overpaying hurt my credit score?
No. Overpaying is a positive signal if anything. What can cause a problem is overpaying so heavily that you cannot cover other commitments, because missed payments elsewhere do damage your file.
What is an early repayment charge?
A fee for repaying more than your allowance during a fixed or discounted period, usually a percentage of the amount repaid and often stepping down each year. It is set out in your mortgage offer.
Should I overpay or reduce the term at remortgage?
Shortening the term at remortgage locks in the discipline and normally costs less than the same reduction achieved through voluntary overpayments, but it removes flexibility. Overpaying keeps the lower contractual payment as a safety net.