BuyMeWhiskey

Mortgage repayment calculator

Updated

Enter the property price, your deposit, the interest rate and the term. The calculator shows repayment and interest-only payments, total interest and a yearly balance table.

How it works

On a repayment mortgage each payment covers that month's interest plus some capital, so the debt is cleared by the end of the term. On interest-only, you pay just the interest and still owe the full loan at the end, so you need a separate plan to repay it.

Rates are rarely fixed for the whole term. Use the rate you expect for the fixed period, then re-run with a likely follow-on rate to see the range of payments you might face.

The formula

Loan P = price − deposit. Repayment: M = P·r(1+r)n / ((1+r)n − 1) with r = annual rate / 12 and n = years × 12. Interest-only: M = P × annual rate / 12. Loan-to-value: LTV = P / price.

Worked example

A £300,000 home with a £30,000 deposit leaves a £270,000 loan (90% LTV). At 4.5% over 25 years the repayment is £1,500.75 a month, with total interest of £180,224.31. Interest-only would be £1,012.50 a month, but the full £270,000 would still be owed after 25 years.

Frequently asked questions

Does this include fees or insurance?

No. Add arrangement fees to the loan if you plan to add them to the mortgage, and budget separately for buildings insurance, ground rent or service charges.

How much do overpayments save?

Overpayments reduce the balance immediately, so every later month's interest is lower. Enter a monthly overpayment to see the new term and interest. Many lenders cap penalty-free overpayments during a fixed deal, so check your terms.

Can I use it for US mortgages?

Yes, the maths is the same. Switch the currency symbol. It does not include US property taxes, homeowners insurance or PMI, which are often collected with the payment.

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General information, not personal financial advice. Results are estimates based on the inputs and assumptions shown.