Mortgage Repayment Calculator — Monthly Payment, Total Interest, Full Term

Enter price, deposit, rate and term to see your monthly repayment, the total interest over the term, and the repayment vs interest-only difference — on screen, no signup. It's the standard amortisation arithmetic every lender's repayment quote is built on; your lender's exact quote may differ because they price by credit, loan-to-value and their own stress tests.

No signup. Standard amortisation arithmetic — a planning figure, not a lender quote or advice.

This check runs on screen, no signup. The full property report is £9.99 Lite / £24.99 Complete — one report, one price, no subscription.

How repayments are calculated

A repayment mortgage uses the standard amortisation formula: the monthly payment is set so that, at your interest rate, the loan reaches exactly zero at the end of the term. Early payments are mostly interest; later payments are mostly capital. This calculator applies that formula directly — M = L·r / (1 − (1+r)−n) with monthly rate r and n monthly payments — which is why its output matches the shape of any lender's quote even though it isn't one.

Worked example: borrow £225,000 (a £250,000 home with a £25,000 deposit) at 4.5% over 25 years and the repayment is about £1,251 a month — roughly £375,000 repaid in total, of which about £150,000 is interest.

Repayment vs interest-only

Interest-only looks cheaper because it is paying for less: the monthly cost covers only the interest, and the entire loan is still owed at the end of the term. It has legitimate uses (some landlords, bridging situations, strong repayment vehicles) but for most owner-occupiers the repayment basis is the realistic planning number. The calculator shows both, with the loan left at term end made explicit.

What moves your payment

Three levers: the rate (each percentage point matters more than any other input), the term (longer is cheaper monthly, dearer in total), and overpayments (which shorten the term from the inside). This page is arithmetic, not advice — it can't predict rates or tell you which product to pick, and we are not a lender or broker.

The repayment is only the recurring cost

Buying has one-off costs on top of the deposit — stamp duty, conveyancing, survey and search fees — and owning has recurring lines beyond the mortgage: council tax, energy, insurance, and service charge on leasehold flats. The true cost of owning calculator stacks those into one monthly figure.

Frequently asked questions

At 4.5% over 25 years, about £1,390 a month on a repayment basis — roughly £417,000 repaid in total, of which around £167,000 is interest. Change any input and the calculator reworks the figure using the same standard amortisation formula.
Monthly, yes; in total, no. On a £250,000 loan at 4.5%, stretching from 25 to 35 years cuts the payment from about £1,390 to about £1,183 a month — but adds roughly £80,000 of extra interest over the life of the loan. Run both terms through the calculator to see the trade-off for your numbers.
A repayment mortgage clears the loan by the end of the term — each payment covers interest plus a slice of capital. Interest-only costs less per month but repays nothing: the full loan remains due at the end, so you need a credible repayment plan. The calculator shows both side by side for the same loan.
No — it's the standard repayment arithmetic, not a quote. Lenders price by credit history, loan-to-value and their own affordability stress tests, so treat this as a planning figure. Only a lender or broker can tell you the rate and amount you'd actually be offered.
Overpaying shortens the term and cuts total interest, and most fixed deals allow around 10% a year without an early-repayment charge — but check your product's terms, as they vary. Whether overpaying beats saving or investing the money depends on your rate and circumstances. Not financial advice.

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