Mortgage overpayment calculator
What paying a bit more than you have to each month does to the total interest, and to the date the mortgage is gone.
What you owe today, not what you originally borrowed.
The rate you are on, or one you have been quoted. We are not permitted to publish rates.
On top of the normal payment.
Paid in now, if you have one. Leave it empty otherwise.
- Normal payment
- £1,028 a month
- You would pay
- £1,228 a month
- Cleared in
- 18 years 7 months
- Instead of
- 25 years
- Interest without overpaying
- £123,487
- Interest if you do
- £88,018
Assumes the rate holds for the whole term and the monthly payment stays the same, so the term shortens. Most deals cap penalty-free overpayments at ten percent of the balance a year; past that an early repayment charge usually applies.
Why a modest overpayment does so much
Every pound you overpay stops costing you interest for the whole of the remaining term, which on a long mortgage means each pound works for decades. That is why a couple of hundred a month can take years off the end, while the same money arriving late in the term changes very little.
Most deals allow ten percent a year
A typical fixed deal lets you overpay up to ten percent of the outstanding balance each year without penalty. Go past that and an early repayment charge usually applies, which can swallow years of the saving in one go. The exact allowance is in your offer document, and it is worth checking before you set anything up.
Ask for the term to reduce, not the payment
When you overpay, some lenders recalculate and quietly lower your monthly payment instead. That feels pleasant and undoes most of the point. Tell them to keep the payment where it is and shorten the term, because the shorter term is where the interest saving actually lives.
It is not automatically the best home for the money
Expensive unsecured debt is almost always worth clearing first, and money overpaid into the mortgage is hard to get back out in an emergency. If savings would earn more after tax than the mortgage is costing, the arithmetic points the other way. Worth an honest look before you commit to it.
This is a calculator, not advice
Everything above is arithmetic on the figures you typed in. It is not a recommendation, not a decision in principle, and not an offer. What it is good for is telling you whether you are in roughly the right area before you spend an afternoon on property listings.
A number is not an answer.
These tools give you the shape of it. What they cannot do is tell you which lender will say yes, and on what terms, which is the part we actually do. The first conversation costs nothing and commits you to nothing.