Mortgage Calculators
Mortgage Repayment Calculator
See what a mortgage actually costs each month, what it costs in total, and how much of that is interest rather than the loan itself.
- Monthly payment on any amount, rate and term
- Total interest across the whole term
- Repayment compared with interest only
- Whole-of-market advice on which suits you
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rates, fees & total borrowing
Product fees, valuation and legal costs sit on top of these figures. 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.
What the numbers are actually telling you
A repayment mortgage clears the loan and the interest over the term. Every payment does two jobs: it pays that month’s interest, and whatever is left reduces the balance. Early on almost all of it is interest, which is why overpaying in the first few years has far more effect than overpaying near the end.
The term does more to your monthly payment than most people expect, and the trade is not free. Stretching from 25 to 35 years lowers what you pay each month, but you pay interest for another decade. Run both in the calculator and compare the total repaid, not just the monthly figure.
Interest only is a different product. The payment covers the interest and nothing else, so the full balance is still owed at the end. Lenders will want a credible plan for repaying it, and on residential cases that plan is scrutinised closely.
A worked example, start to finish
Take a £250,000 mortgage at 4.5% over 25 years. The monthly payment is roughly £1,390 and the total repaid across the term is about £417,000, of which around £167,000 is interest. That interest figure is the number most people never see quoted, and it is the one that makes the trade-offs obvious.
Now stretch the same loan to 35 years. The payment falls to roughly £1,183, which is £207 a month easier. But the total repaid climbs to about £497,000, so the extra decade costs roughly £80,000 in additional interest. Neither answer is wrong. A younger buyer stretching the term to get on the ladder, intending to shorten it at the first remortgage, is making a perfectly sensible decision. Someone taking 35 years by default because the payment looked comfortable is not.
Run the same loan on interest only and the payment drops to about £938 a month, but after 25 years the full £250,000 is still owed. On buy to let that is normal and expected. On a residential mortgage the lender will want documented evidence of how the capital will be repaid, and a vague intention to sell the house is rarely accepted on its own.
What the calculator cannot see
It does not know your credit file. Two people borrowing the same amount over the same term can be offered rates a long way apart, and with adverse credit on file the gap widens considerably. The calculator assumes you get the rate you type in; whether a lender will offer it is a separate question.
It does not include fees. Product fees, valuation fees, legal costs and any broker fee sit on top of the figures shown. On a small loan a £1,495 product fee attached to a low headline rate can easily cost more than a fee-free deal a quarter of a point higher.
And it assumes the rate holds for the whole term, which it almost never does. Most people are on a fixed rate for two or five years and then move onto something else. The honest way to use these numbers is as a comparison between options, not as a forecast of twenty-five years of payments.
Where to go next
Independent sources
- MoneyHelper repayment calculator — The government-backed calculator, useful as a second opinion
- MoneyHelper on interest rates — Fixed, tracker and variable rates explained impartially
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Frequently Asked Questions – Mortgage Repayment Calculator
How is a monthly mortgage payment worked out?
It uses the loan amount, the interest rate and the term. Each month you are charged interest on the balance outstanding, and the payment is set so that the balance reaches zero exactly at the end of the term. Because the balance falls over time, the interest portion of each payment falls with it and the capital portion rises.
Why does most of my early payment go on interest?
Because interest is charged on what you still owe, and at the start you owe almost the whole loan. On a 25 year mortgage it is common for more than half of the first few years’ payments to be interest. This is also why an overpayment made in year two saves far more than the same overpayment made in year twenty.
Is a longer term cheaper?
It is cheaper each month and more expensive overall. Extending the term spreads the same debt over more payments, so each one is smaller, but you are borrowing for longer and paying interest for longer. Compare the total repaid figure in the calculator before deciding.
What is the difference between repayment and interest only?
A repayment mortgage clears the loan by the end of the term. An interest only mortgage does not: you pay the interest each month and the original amount is still owed at the end. Interest only is mainly used for buy to let, and on residential cases lenders require evidence of how you will repay the capital.
Does this calculator account for fees?
No. It shows the cost of the borrowing itself. Product fees, valuation fees, legal costs and any broker fee sit on top, and a low rate with a high product fee can work out worse than a slightly higher rate with no fee, particularly on smaller loans.
Will my payment change during the mortgage?
Yes, unless you are on a fixed rate for the whole term, which is rare. When a fixed period ends you usually move to the lender’s standard variable rate, which is normally higher. Most people remortgage or take a new product before that happens.