Mortgage Calculator UKFree online financial calculator — instant results, no sign-up
Repayment or interest-only mortgage payment in pounds.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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About the Mortgage Calculator UK
This calculator estimates monthly mortgage payments and total borrowing costs for home buyers and homeowners in the UK. It supports both repayment (capital and interest) and interest-only mortgage structures based on your borrowing amount, annual interest rate, and term length.
- Loan amount
- Total amount borrowed in pounds sterling (£), typically between £25,000 and £2,000,000.
- Rate
- Annual nominal interest rate as a percentage, typically between 1% and 15%.
- Term
- Mortgage duration in years, commonly between 5 and 40 years.
- Type
- Selection between 'Repayment' (capital and interest) and 'Interest only'.
Formula and method
For Repayment: M = P × [r(1 + r)^n] / [(1 + r)^n − 1] and Total Repaid = M × n For Interest only: M = P × r and Total Repaid = (M × n) + P
- PLoan principal amount (£)
- rMonthly interest rate, equal to annual rate divided by 1,200
- nTotal number of monthly payments (Term in years × 12)
- MMonthly mortgage payment (£)
The tool converts the annual interest rate into an effective monthly rate and calculates total payments across the selected term in months. For repayment mortgages, it calculates an amortizing monthly instalment using standard annuity formulas, while interest-only loans calculate the monthly interest charge and append the original principal to the total repaid figure.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Loan amount250000 £
- Rate4.5 %
- Term25 years
- TypeRepayment
Results
- Monthly payment£1,389.58
- Total repaid£416,874.36
How to use the Mortgage Calculator UK
- 1Enter the total amount borrowed under Loan amount (£).
- 2Enter the expected annual interest rate and the loan duration in years.
- 3Select your mortgage structure as either 'Repayment' or 'Interest only'.
- 4Review the resulting monthly payment and total amount repaid over the full term.
Reading your result
The monthly payment shows your regular required outlay each month under the specified rate. For repayment mortgages, total repaid reflects both loan principal and cumulative interest. For interest-only mortgages, total repaid reflects the sum of all monthly interest charges plus the original loan principal due at term end.
Limitations
The calculation assumes a constant interest rate throughout the entire term, whereas most UK mortgages involve fixed introductory periods followed by a Standard Variable Rate (SVR). It also does not factor in mortgage arrangement fees, valuation charges, early repayment charges, or Stamp Duty Land Tax.
Common questions
How does a repayment mortgage differ from an interest-only mortgage?+
A repayment mortgage pays down both the interest and the original loan balance each month, clearing the debt entirely by the end of the term. An interest-only mortgage covers only the monthly interest, leaving the original principal balance to be repaid in full at the end via savings, investments, or property sale.
Does this calculation include UK mortgage arrangement or broker fees?+
No. The calculation only covers the loan balance and interest. If your lender charges an arrangement fee (often £999 to £2,000) and adds it to the mortgage, you should add that amount to your loan principal input to see its effect.
What happens when my fixed-rate deal ends?+
In the UK, fixed rates typically last 2 to 5 years. After that period, your lender will move you to their Standard Variable Rate (SVR) unless you remortgage or switch to a new product, which will alter your monthly payment.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.