A £200,000 repayment mortgage over 25 years costs £1,001 a month at 3.5%, £1,112 at 4.5% and £1,228 at 5.5%. Each percentage point on the rate adds roughly £110 a month at that loan size, and each £50,000 of borrowing adds about £280 at 4.5%. Stretching the term from 25 to 35 years cuts the monthly payment by £165 but adds £64,000 of interest over the life of the loan. The tables below give the monthly figure for the most common loan sizes, rates and terms, all from the same repayment formula that lenders use.
Monthly repayments over 25 years
| Loan | 3.5% | 4% | 4.5% | 5% | 5.5% | 6% |
|---|---|---|---|---|---|---|
| £150,000 | £751 | £792 | £834 | £877 | £921 | £966 |
| £200,000 | £1,001 | £1,056 | £1,112 | £1,169 | £1,228 | £1,289 |
| £250,000 | £1,252 | £1,320 | £1,390 | £1,461 | £1,535 | £1,611 |
| £300,000 | £1,502 | £1,584 | £1,667 | £1,754 | £1,842 | £1,933 |
| £400,000 | £2,002 | £2,111 | £2,223 | £2,338 | £2,456 | £2,577 |
The payment is fixed for the life of a fixed-rate deal and then moves to the lender’s standard variable rate or a new deal, so the relevant comparison at remortgage is the row for your remaining balance across the two rates. A borrower with £200,000 outstanding whose 2021 fix at 2% ends and who moves to 4.5% sees the payment rise from about £848 to £1,112. The mortgage repayment calculator gives the figure for any loan, rate and term, with the split between interest and capital in each year, and the mortgage repayment pages set out every rate and term for each loan size from £100,000 to £600,000.
How the term changes the cost
| Term on £200,000 at 4.5% | Monthly | Total interest over the term |
|---|---|---|
| 15 years | £1,530 | £75,398 |
| 20 years | £1,265 | £103,672 |
| 25 years | £1,112 | £133,499 |
| 30 years | £1,013 | £164,813 |
| 35 years | £947 | £197,536 |
| 40 years | £899 | £231,580 |
A longer term lowers the payment at a steep price: going from 25 to 40 years saves £213 a month and costs £98,000 more in interest, and the loan runs into the borrower’s seventies. Lenders now offer 35 and 40-year terms routinely to first-time buyers, and the sensible use of one is as a safety margin: take the longer term for a lower contractual payment, then overpay to the 25-year figure while you can. Most lenders allow overpayments of 10% of the balance a year without penalty during a fixed deal. On £200,000 at 4.5% over 25 years, overpaying £100 a month clears the loan 42 months early and saves £21,142 of interest; a single £10,000 lump sum in the first year saves £19,300 and 26 months. The mortgage overpayment calculator shows the interest and years saved by any monthly or lump sum overpayment.
How the rate changes the cost
| Rate on £200,000 over 25 years | Monthly | Total interest |
|---|---|---|
| 3.5% | £1,001 | £100,374 |
| 4.5% | £1,112 | £133,499 |
| 5.5% | £1,228 | £168,452 |
Two points of rate add £33,000 to £35,000 of interest per point over a 25-year term on £200,000. That is why a product fee of £999 or £1,499 for a lower rate is often worth paying on a large loan and rarely on a small one: on £200,000 a rate 0.2 points lower saves about £22 a month, £528 over a two-year fix, so a £999 fee loses money, while on £400,000 the same gap saves £1,056 and the fee pays for itself. The remortgage break-even calculator makes that comparison for any two deals and fees.
Interest only
On an interest-only mortgage the payment covers only the interest, so £200,000 at 4.5% costs £750 a month against £1,112 on repayment, but the £200,000 is still owed in full at the end of the term. Lenders restrict interest-only lending to borrowers with a credible repayment plan, such as an investment portfolio, other property or a large pension lump sum, and usually to lower loan-to-value ratios. The difference of £362 a month is not a saving: it is capital that has to be found another way. The interest-only calculator compares the two structures and shows the balance left at each point.
How much a lender will offer
Affordability is assessed on income, existing commitments and a stressed rate rather than on the headline payment. Most lenders cap borrowing at around four and a half times income, with five or five and a half times available to higher earners and some first-time buyers, and they test whether the payment remains affordable if rates rise. A couple earning £70,000 between them with £300 a month of loan and card repayments could borrow about £266,000 at four times assessable income, £299,000 at four and a half times and up to £365,000 at five and a half, and a 10% deposit on a £350,000 home is £35,000 before stamp duty and fees. The mortgage affordability calculator estimates the range for your income and commitments, and our stamp duty guide covers the tax on the purchase.
Common questions
How much is a £200,000 mortgage a month? £1,112 a month over 25 years at 4.5%, £1,001 at 3.5% and £1,228 at 5.5%. Over 35 years at 4.5% it is £947.
How much does 1% on the rate add? About £55 a month per £100,000 borrowed over 25 years, so £110 on a £200,000 loan and £220 on £400,000.
Is a longer mortgage term a bad idea? It lowers the monthly payment but raises total interest sharply: 40 years instead of 25 on £200,000 at 4.5% costs an extra £98,000. It is reasonable as a safety margin if you overpay.
How much can I borrow? Typically four to four and a half times household income, less for large existing commitments, and up to five and a half times for some borrowers. Lenders also stress test the payment against higher rates.
Is interest only cheaper? Only month to month. £200,000 at 4.5% costs £750 interest only against £1,112 on repayment, but the whole loan remains outstanding and must be repaid from another source.
Should I pay a product fee for a lower rate? On large loans, often yes; on small loans, usually no. Compare the total cost of each deal over the fixed period including the fee.
Information, not financial advice. Monthly figures are from the site’s repayment calculator using the standard amortisation formula and illustrative rates; actual offers depend on the lender, the loan-to-value ratio and your circumstances. Speak to a mortgage adviser before committing to a deal.