Calculate your monthly payments and visualize your mortgage over time
£1,334
£240,000
80%
£60,000
Total Interest Paid
£160,199
Total Money Repaid
£400,199
Explore how overpayments can reduce your mortgage term and save on interest
Payment will be applied in month 1
Add a monthly overpayment or lump sum to see the impact on your mortgage
Starting Balance
£240,000
Mid-term Balance
£152,829
Final Balance
£0
A mortgage is one of the largest financial commitments you will ever make. Whether you are a first-time buyer trying to understand what you can afford, or a homeowner considering remortgaging, knowing your numbers upfront saves time and prevents nasty surprises down the line. This mortgage calculator gives you an instant view of your monthly repayment, total interest paid, and how your loan balance reduces year by year.
In the UK, most residential mortgages are repayment mortgages, meaning each monthly payment reduces both the interest and the loan balance. The split between interest and capital changes over time — early payments are mostly interest, while later payments chip away more of the principal. This is called amortisation, and our calculator visualises this with a full amortisation schedule so you can see exactly where your money goes each year.
Use this tool to compare different deposit sizes, interest rates, and loan terms. Try increasing your deposit by £10,000 and watch how much less interest you pay overall. Experiment with shorter terms — a 20-year mortgage has higher monthly payments than a 25-year one, but saves a significant amount in total interest. You can also model overpayments to see how even small additional monthly payments can cut years off your mortgage term.
The calculator uses the standard amortisation formula used by UK lenders. Your monthly payment is calculated as: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. This formula ensures the loan is fully repaid at the end of the term with equal monthly payments throughout.
Overpayment calculations reduce the outstanding principal ahead of schedule, recalculating the remaining interest and term accordingly. All figures are estimates based on the inputs you provide and assume a constant interest rate for the full term. Speak to a mortgage broker or your lender for a personalised illustration that accounts for your credit history and the specific product you are applying for.