UK Mortgage Calculator
Your monthly mortgage payment in pounds, repayment vs interest-only, the total interest you'll pay, how much overpaying saves, and a term comparison from 15 to 35 years. Results update instantly, with every step shown. No sign-up.
Assumes the same interest rate for the whole term, charged monthly. Real deals usually change rate when an initial fixed or tracker period ends, and may have fees and overpayment limits.
- Loan£0
- Loan to value0%
- Total interest (no overpayment)£0
- Total paid (no overpayment)£0
- Still owed at the end£0
- Interest-only payment for comparison£0
Quick answer
A £240,000 repayment mortgage at 4.5% over 25 years costs about £1,334.00 a month and £160,199 in total interest. Fixed rate for the whole term, interest charged monthly. Real deals change rate after the initial period and may charge fees.
Overpayments
Same rate and term. For a repayment mortgage, overpaying shortens the term; for interest-only, it reduces what you owe at the end.
| Monthly payment | Time to clear | Total interest | Owed at end |
|---|
Term comparison (repayment)
Same loan and rate over different terms. Your term is highlighted.
| Term | Monthly payment | Total interest | Total repaid |
|---|
Repayment vs interest-only
- Repayment: each monthly payment covers that month's interest plus some of the loan, so the balance reaches zero at the end of the term. Early payments are mostly interest; later ones mostly capital.
- Interest-only: you pay just the interest, so the balance never falls. You need a separate plan (savings, investments or selling the property) to repay the full loan at the end.
Overpaying
An overpayment goes straight off the balance, so less interest is charged every month after it. In this calculator your normal payment stays the same and the overpayment is added on top, so the mortgage ends early. Many lenders let you overpay a set amount each year without a charge; above that, an early repayment charge may apply. Check your mortgage offer.
Buying costs: stamp duty
This calculator covers the mortgage only. If you're buying in England or Northern Ireland, work out Stamp Duty Land Tax with the UK stamp duty calculator.
The formula
- P — the loan: property price − deposit
- r — annual interest rate ÷ 12
- n — term in months
- Total interest — added up month by month from the balance, so overpayments are included exactly
See the formula with your own numbers
These update live from the calculator inputs above.
Frequently asked questions
How is a UK repayment mortgage payment worked out?
With the standard amortisation formula: monthly payment = P × r(1+r)^n ÷ ((1+r)^n − 1), where P is the loan, r is the annual rate ÷ 12 and n is the number of months. Each payment covers that month's interest and pays off some of the loan.
What is the difference between repayment and interest-only?
A repayment mortgage pays off the loan by the end of the term. An interest-only mortgage only pays the interest each month (loan × annual rate ÷ 12), so monthly payments are lower but the whole loan is still owed at the end.
How much does overpaying a mortgage save?
Every extra pound reduces the balance that interest is charged on. On a repayment mortgage, keeping the same payment plus an overpayment clears the loan early and cuts the total interest. Check your lender's overpayment limits and any early repayment charges first.
Is a longer mortgage term cheaper?
A longer term lowers the monthly payment but increases the total interest, because the loan is outstanding for longer. The term comparison table shows both for 15 to 35 years.
Does this include stamp duty?
No. This calculator only covers the mortgage. Use the UK stamp duty calculator for Stamp Duty Land Tax in England and Northern Ireland.
Method & sources
- Calculation: standard amortisation (the same formula as our other loan calculators): M = P·r(1+r)^n ÷ ((1+r)^n − 1) with r = annual rate ÷ 12; interest-only M = P × r. Totals and overpayments are simulated month by month.
- No tax rules are used. Stamp duty is handled separately by the UK stamp duty calculator.
- Verification: automated tests check standard results (for example £200,000 at 5% over 25 years = £1,169.18 a month), interest-only totals and overpayment terms against the closed-form payoff formula.
- Reviewed: .
Educational estimate only, not personal financial advice or a mortgage offer. Lenders' rates, fees, overpayment limits and affordability checks vary; rules can change. Check your mortgage illustration or speak to a qualified adviser.
Run your own numbers
Enter your price, deposit, rate and term to see your monthly payment.
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