Estimate your monthly mortgage repayment, including buildings insurance and service charges.
Rates as of Q2 2025 (example)
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A mortgage calculator estimates your monthly repayment on a home loan based on the property price, your deposit, the mortgage term, and the interest rate. This UK version also lets you add buildings insurance and a service charge (common for leasehold flats), so you can see a more complete picture of your total monthly housing cost — plus the effect of any monthly overpayments on your term and total interest.
The principal & interest portion of your payment is calculated using the standard amortising loan formula, based on the amount you're borrowing (property price minus deposit), the interest rate, and the term. Buildings insurance and any service charge are added on top as separate monthly costs.
Formula: Loan Amount = Property Price − Deposit. Monthly Payment = [Loan Amount × r × (1+r)n] / [(1+r)n − 1], where r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the number of monthly payments (years × 12).
Example: For a £350,000 property with a £70,000 deposit, the loan amount is £280,000. At a 5.25% interest rate (example rate — enter your actual rate) over 25 years, the principal & interest payment is roughly £1,678 per month. Adding £150/year buildings insurance (about £12.50/month) brings the total to around £1,690/month, before any service charge or overpayments. (Note: all figures in this example are for illustration purposes only and do not represent an offer of credit.)
Most UK residential mortgages are repayment mortgages, where each monthly payment covers both interest and a portion of the capital, gradually reducing the balance to zero by the end of the term — this calculator models a repayment mortgage. Interest-only mortgages, where you only pay interest each month and repay the capital separately at the end of the term, work differently and aren't modelled here. UK mortgages are typically taken on fixed-rate deals (commonly 2, 5, or 10 years) or variable/tracker rates linked to the Bank of England base rate — when a fixed deal ends, most borrowers remortgage onto a new rate rather than reverting to their lender's standard variable rate (SVR), which is usually higher. Your loan-to-value ratio (LTV) — the loan amount as a percentage of the property value — significantly affects the rates available to you, with lower LTVs (larger deposits) generally qualifying for better rates. Buyers should also budget separately for Stamp Duty Land Tax (SDLT) on the purchase, which isn't included in this calculator (example structure — see the Stamp Duty Calculator).
With a repayment mortgage, each monthly payment covers interest plus a portion of the loan amount, so the balance reduces to zero by the end of the term. With an interest-only mortgage, you only pay interest each month, and the full loan amount remains due at the end of the term, to be repaid from savings, investments, or sale of the property. This calculator models a repayment mortgage.
No — the default is an example only. Mortgage rates vary by lender, product type, fixed-rate period, and your loan-to-value ratio. Enter the actual rate from a mortgage offer or quote for an accurate result.
No. Stamp Duty Land Tax (SDLT) is a separate cost paid when you buy a property in England or Northern Ireland (with different rules in Scotland and Wales), and isn't included in this monthly payment calculation. Use the Stamp Duty Calculator to estimate that cost separately.
When a fixed-rate or other introductory deal ends, most borrowers remortgage onto a new fixed or tracker deal, either with their existing lender or a new one. If you don't remortgage, you'll typically move onto your lender's standard variable rate (SVR), which is usually higher than fixed deal rates.
LTV is your loan amount as a percentage of the property value. Lower LTVs (achieved with a larger deposit) generally qualify for better interest rates, as they represent less risk to the lender. Increasing your deposit, even slightly, can sometimes move you into a better LTV band with meaningfully lower rates.
It depends on your mortgage product. Many UK mortgages allow penalty-free overpayments up to a certain limit each year (often around 10% of the outstanding balance), but exceeding that limit during a fixed-rate period can trigger an early repayment charge. Check your mortgage terms before making large overpayments.
Disclaimer: The information, rates, and figures provided on this page are for educational and illustrative purposes only and do not constitute financial advice or a mortgage offer. The default interest rate is a sample value and does not reflect rates currently available from any specific lender. Mortgage rates, fees, and lending criteria change frequently. Always obtain a personalised quote from a mortgage lender or broker and consult a qualified financial adviser before making any borrowing decisions.