CALCULATOR

Mortgage repayment calculator

Work out the monthly payment on a repayment mortgage, and what the whole thing costs in interest over the term. Nothing is stored and nothing is sent anywhere.

Amount borrowed
Rate, % a year
Term, in years
Monthly paymentCalculating...
Total interest over the termCalculating...
Total repaidCalculating...

Risk warning. Your home may be repossessed if you do not keep up repayments on your mortgage. Think carefully before securing other debts against your home. This calculator is an illustration only. It is not a personal recommendation and it is not an offer of credit.

This is a calculation, not a quote and not advice. It assumes one rate for the whole term, which almost never happens in practice, so treat the total interest figure as an illustration rather than a forecast.

How a repayment mortgage is calculated

Every monthly payment on a repayment mortgage does two jobs at once: it pays the interest that has built up since last month, and it chips away at the amount you still owe. The payment stays the same, but the split inside it does not.

In the early years most of your payment is interest, because the balance it is charged on is still large. As the balance falls, the interest portion shrinks and more of the same payment goes to clearing the debt. That is why overpaying early is worth so much more than overpaying late, and why the total interest figure is so sensitive to the term.

The formula itself is fixed. The monthly payment equals the amount borrowed multiplied by the monthly rate, divided by one minus one plus the monthly rate raised to the power of minus the number of months. The monthly rate is simply the annual rate divided by twelve.

What this calculator does not know

Whether a lender would actually offer you this

Affordability is assessed on income, outgoings, credit history and stress-tested rates, and it varies enormously between lenders. A payment you could comfortably make is not the same as a loan a lender will approve.

What happens when your fixed rate ends

This assumes one rate for the whole term. In reality you will remortgage several times, and each time the payment changes. The real total cost depends on decisions you have not made yet.

Fees, insurance and everything else

Arrangement fees, valuation fees, legal costs and any protection you put alongside the mortgage all sit outside this figure.

Whether interest-only would suit you better

This is a repayment calculation. Interest-only lowers the monthly figure and leaves the capital outstanding, which is a different decision with different consequences.

Try the others

Overpayment

See what paying a little extra each month does to the interest and the term.

Mortgage overpayment calculator

Compound interest

What regular saving turns into over time, and how much of it is growth.

Compound interest calculator

Mortgage advice

The part a calculator cannot do: working out which lender will say yes.

How we handle mortgages

The number is the easy part.

Which lender will actually lend it, on your accounts, is the bit worth a conversation.

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