Calculate your estimated monthly mortgage payment, total interest cost and loan-to-value (LTV) ratio. Enter your property price, deposit, interest rate and mortgage term below — get instant results with no sign-up required.
Enter your property price, the deposit you plan to put down, your expected annual interest rate and how many years you want the mortgage to run. The calculator uses the standard amortisation formula to work out the equal monthly repayment that would pay off your loan by the end of the term.
Loan Amount — property price minus deposit. This is what you are actually borrowing.
Monthly Payment — the amount you would pay every month across the full term.
Total Interest — the additional cost of borrowing on top of the loan amount.
LTV Ratio — loan as a percentage of property value. Below 80% LTV typically unlocks better rates.
Property £300,000, deposit £30,000, rate 4.5%, 25-year term → loan £270,000, monthly payment approximately £1,500, total interest approximately £180,000, LTV 90%.
The mortgage calculator estimates the monthly repayment you would make on a standard capital-and-interest repayment mortgage. It takes four inputs — property price, deposit, annual interest rate and term in years — and applies the standard amortisation formula to produce a consistent monthly payment that clears the loan in full by the final month.
The tool also calculates your loan-to-value (LTV) ratio, which is the loan amount expressed as a percentage of the property value. LTV is one of the most important figures in mortgage lending — it determines which products you can access and at what rate. A borrower at 60% LTV is considered lower-risk by lenders and typically qualifies for significantly lower interest rates than one at 90% or 95%.
For the most useful result, use realistic figures. Research the current mortgage rates from major UK lenders before entering a rate — inputting 2% in a 4.5% market will give you an unrealistically low monthly figure. Check the Bank of England base rate and published lender products as a starting point.
Try running multiple scenarios: change the deposit amount to see how raising it by £10,000 or £20,000 affects both the monthly payment and the LTV. Try extending the term from 25 to 30 years to see the reduction in monthly payment versus the increase in total interest paid. These side-by-side comparisons are often more useful than a single estimate.
This calculator is a planning tool, not a mortgage offer. You should speak to a qualified mortgage broker or financial adviser before making any application. A broker can access the whole market, check your credit position, advise on product fees versus headline rate trade-offs, and ensure the mortgage is affordable based on your full financial picture.
For official affordability guidance, the Money and Pensions Service (moneyhelper.org.uk) offers free, impartial advice on mortgages and property purchase.
Common questions about this calculator and how to use it.