Mortgage Repayment Calculator
Work out your monthly payment, total interest, and a year-by-year amortisation schedule.
| Year | Principal paid | Interest paid | Balance remaining |
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How the mortgage repayment calculator works
Enter your loan amount, the annual interest rate, and the mortgage term in years. Choose repayment if you want the loan paid off in full by the end of the term, or interest-only if your monthly payment covers interest alone and the capital is repaid separately at the end.
The calculator shows your monthly payment, total interest paid over the full term, and a year-by-year amortisation schedule so you can see exactly how the balance falls (or doesn't, for interest-only) over time.
Repayment vs interest-only mortgages
A repayment mortgage is the most common type in the UK: every monthly payment covers some interest and some capital, so the loan is guaranteed to be paid off by the end of the term as long as payments are kept up. Monthly payments are higher than interest-only, but you build up equity throughout.
An interest-only mortgage has lower monthly payments because you're only paying the interest — the capital balance stays the same until the end of the term, at which point the full loan amount is due. Lenders usually require evidence of a credible repayment strategy (such as an ISA, pension, or planned property sale) before approving an interest-only mortgage.
Frequently asked questions
How is my monthly mortgage payment calculated?
For a repayment mortgage, the calculator uses the standard amortisation formula based on your loan amount, monthly interest rate, and number of monthly payments, so the loan is fully paid off by the end of the term. For interest-only, the monthly payment is simply the loan balance multiplied by the monthly interest rate.
What's the difference between repayment and interest-only?
With repayment, each payment covers some interest and some capital, so the balance shrinks every month. With interest-only, your payment covers interest only — the capital balance never reduces, and you need a separate plan to clear the loan at the end of the term.
What is an amortisation schedule?
It shows how each payment splits between interest and capital over the life of the loan. Early on, most of each payment goes towards interest; as the balance falls, more goes towards capital. This tool shows the schedule broken down by year.
Does this calculator include fees or overpayments?
No. It shows the standard monthly payment based on loan amount, interest rate, and term only — it doesn't account for arrangement fees, early repayment charges, or any overpayments you might make.
Will my interest rate stay the same for the whole term?
This calculator assumes a single fixed rate for the whole term you enter. In reality, most UK mortgages have an initial fixed or tracker rate (typically 2–5 years) before reverting to the lender's standard variable rate, so real payments are likely to change during the term.