Mortgage Calculator UK
Calculate your monthly UK mortgage payments in pounds sterling. Enter the property price, deposit, rate, and term for an instant result.
Loan details
Your monthly payment
What is a Mortgage Calculator UK?
A Mortgage Calculator UK is a free tool that estimates your monthly mortgage payments in pounds sterling. Enter the property price, deposit, interest rate, and loan term to get an instant snapshot of what your mortgage could cost each month and over the full term.
How to calculate mortgage manually (the formula)
The standard amortisation formula is: M = P [ r(1+r)n ] / [ (1+r)n – 1 ] where M is the monthly payment, P is the loan amount (property price minus deposit), r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments (term in years × 12).
Example calculation
For a £300,000 property with a £45,000 deposit (15%), a 5.5% annual rate, and a 25-year term: the loan amount is £255,000. The monthly rate is 0.4583% (5.5% ÷ 12). Over 300 payments, the estimated monthly payment is roughly £1,565. The total interest paid over the full term would be about £214,500.
Common mistakes
- Not accounting for interest rate changes — UK fixed-rate deals typically last 2–5 years. After that, you revert to the lender's standard variable rate, which can be much higher.
- Ignoring fees and charges — Arrangement fees, valuation fees, and early repayment charges can add thousands to the overall cost.
- Overlooking stamp duty — Stamp Duty Land Tax is a significant upfront cost. First-time buyers get relief, but others may pay up to 12% on portions above certain thresholds.
- Forgetting about insurance — Most UK lenders require buildings insurance, and life cover is often recommended to protect your family.
- Using an unrealistic deposit — A smaller deposit means a higher loan-to-value ratio, which typically leads to higher interest rates and larger monthly payments.
Frequently asked questions
How does a mortgage calculator work?
A mortgage calculator estimates your monthly payment based on the property price, deposit, interest rate, and loan term. It uses the standard amortisation formula to work out how much you will pay each month.
How much mortgage can I afford in the UK?
Most UK lenders will lend between 4 and 5 times your annual income. Your affordability also depends on your deposit size, credit score, monthly outgoings, and the current Bank of England base rate.
What is included in a mortgage payment estimate?
A full mortgage payment estimate includes the principal and interest, but may also include building insurance and life cover. Unlike US mortgages, UK estimates typically do not include property taxes (council tax) in the monthly payment.
What is the difference between fixed and variable rate mortgages?
A fixed-rate mortgage locks your interest rate for a set period (typically 2 or 5 years), giving predictable payments. A variable rate can change with the Bank of England base rate, which means your payments may go up or down.
Is this calculator free?
Yes, completely free with no sign-up required. Use it as many times as you like.