Residential Mortgage Calculator — Slide to See Your Payment

A residential mortgage calculator works out the monthly payment and total cost of a mortgage on a home you'll live in. You enter the price, deposit, interest rate and term, and it applies the standard repayment formula.

On a repayment mortgage, each payment covers the interest plus a slice of the capital, so the balance falls to zero by the end. On interest-only, you pay just the interest and repay the loan in full at the end.

This residential mortgage calculator shows both, plus a clear breakdown of how much of your money goes on the loan itself versus interest — and, since it's often the biggest one-off cost buyers forget to budget for, an indicative Stamp Duty Land Tax estimate too.

Your interest rate is the biggest lever on your monthly payment. In mid-2026 the average 5-year fix is around 5.5% and the average 2-year fix around 5.7%, with the sharpest 60% LTV deals available from roughly 4.25%–4.5%. The Bank of England base rate sits at 3.75%.

When a deal ends you roll onto the lender's standard variable rate (SVR), averaging about 7.1% — often £300+ a month more on a typical loan. That's why most people switch before their deal ends; our remortgage calculator shows the saving. Slide the rate above to feel the difference.

A longer term lowers your monthly payment but raises the total interest, because you borrow for longer. A shorter term costs more each month but saves a lot of interest overall.

For example, extending a £280,000 mortgage from 25 to 35 years cuts the monthly payment noticeably, but can add tens of thousands in interest. Overpaying is a middle path — see how much you'd save with our loan overpayment calculator. Slide the term above to compare instantly.

Your loan-to-value (LTV) is the loan as a percentage of the price. A bigger deposit means a lower LTV, a smaller loan, and usually a cheaper rate.

The key thresholds are 60% (best rates), 75%, 85%, 90% and 95%. Dropping a band can shave around 0.15–0.30% off your rate. Before you buy, check how much you can borrow with the mortgage affordability calculator and get a figure to house-hunt with using the mortgage in principle calculator.

*First-time buyer relief applies only up to a £500,000 purchase price — above that, you pay the standard rates on the whole price, with no partial relief. Additional properties (second homes, buy-to-lets) pay a flat 5% surcharge on top of every standard band, and the surcharge applies from £40,000. SDLT is charged on a slice basis — you only pay the higher rate on the portion of the price within that band, not the whole amount.

These bands apply in England and Northern Ireland only. Scotland uses Land and Buildings Transaction Tax (LBTT), with a nil-rate band of £145,000 (£175,000 for first-time buyers). Wales uses Land Transaction Tax (LTT), with a nil-rate band of £225,000 and no specific first-time buyer relief. Use the buyer type dropdown in the calculator above for an England/NI estimate, and check MoneyHelper's official calculator for Scotland or Wales.

On a repayment mortgage, interest is calculated on your outstanding balance, which is highest right at the start. Since your monthly payment is fixed, most of it covers interest in the early years, with only a small slice actually reducing the capital. As the balance falls, less of each payment goes on interest and more chips away at the loan — so the balance shrinks noticeably faster in the later years than the earlier ones. The year-by-year table in the calculator above shows this in action.

The monthly payment is only half the story. Over a full term, interest can add up to as much as the loan itself — the "where your money goes" bar shows the split clearly. Cutting the rate, shortening the term or overpaying all reduce that interest. If you're buying to rent instead, use the buy to let mortgage calculator; to release cash from a home you own, try the house equity calculator.

Say you buy a £350,000 home with a £70,000 deposit, borrowing £280,000 (80% LTV) over 25 years at 5.4%.

On a repayment basis, the residential mortgage calculator shows a monthly payment of about £1,700. Over the full 25 years you'd repay roughly £510,000 in total, of which about £230,000 is interest — nearly as much as the loan itself.

As a home mover (not a first-time buyer), Stamp Duty on this £350,000 purchase would be around £7,500 — nothing on the first £125,000, 2% on the next £125,000 (£2,500), and 5% on the remaining £100,000 (£5,000). As a first-time buyer, you'd pay nothing at all, since £350,000 sits within the £300,000 nil-rate band plus the 5% band up to £500,000 — specifically 5% on the £50,000 above £300,000, or £2,500. Switch to interest-only and the monthly payment drops to around £1,260, but you'd still owe the full £280,000 at the end. Slide your own figures into the calculator above to compare.

Official sources & further reading: read mortgage guidance at MoneyHelper, use their official Stamp Duty calculator for Scotland and Wales, track the Bank of England base rate, and check GOV.UK's SDLT rules. Browse every tool on the mortgage calculators homepage.