Mortgage Payment Calculator
Estimate monthly payments, total interest over the term, and how the cost changes if rates move.
Optional
- Mortgage amount
- £350,000
- Interest rate
- 4.50%
- Term
- 25 years
- Total monthly payments
- £583,624
- Total interest over the term
- £233,624
- Total amount repaid
- £583,624
What if the interest rate changed?
| Interest rate | Monthly payment |
|---|---|
| 3.50% | £1,752.18 |
| 4.00% | £1,847.43 |
| 4.50% (your rate) | £1,945.41 |
| 5.00% | £2,046.07 |
| 5.50% | £2,149.31 |
Figures are estimates for guidance only and are not a mortgage illustration or personal advice. Actual payments depend on the lender's calculation method, product terms and your circumstances. Your home may be repossessed if you do not keep up repayments on your mortgage.
How are mortgage payments calculated?
A repayment mortgage is amortised: each monthly payment covers the interest for that month and repays a slice of the capital, sized so the balance reaches zero at the end of the term. Early payments are mostly interest; later ones are mostly capital.
Repayment or interest-only?
Interest-only payments are lower because nothing is being repaid. The trade-off is that the original loan is still outstanding at the end of the term and needs a credible repayment plan. Lenders apply their own criteria to interest-only lending, and the two approaches are sometimes combined.
How does the interest rate affect monthly repayments?
Small rate movements make a meaningful difference over a long term. The table above shows the same mortgage at a percentage point either side of your rate — a useful way to sense-check what you would still be comfortable paying if your deal ended in a higher-rate market.
Does adding a product fee to the mortgage cost more?
Normally yes, because the fee is borrowed over the whole term and attracts interest. A lower rate with a higher fee can still win on a large loan, so compare the total cost over the deal period rather than the headline rate alone.
What happens if mortgage rates rise?
On a fixed rate nothing changes until the deal ends; on a tracker or variable rate the payment moves with the rate. Planning for the payment at the end of your fixed period — not just the payment today — is one of the more valuable things to do before you commit.
Why might an actual lender payment differ slightly?
Lenders differ in how they apply interest, when in the month they collect payments, and how they treat part months and rounding. Expect small differences against any calculator, including this one.
Frequently asked questions
- How are monthly mortgage payments worked out?
- A repayment mortgage uses the standard amortisation formula, which spreads the loan and the interest evenly across the term so the balance reaches zero at the end. An interest-only payment is simply the annual interest divided by twelve.
- What is the difference between repayment and interest-only?
- On a repayment mortgage each payment clears some capital as well as interest. On interest-only you pay only the interest, so the original balance is still outstanding at the end of the term and must be repaid another way.
- Does adding a product fee to the mortgage cost more?
- Usually yes. A fee added to the loan is borrowed over the full term, so you pay interest on it. Paying it up front keeps the balance lower, if the cash is available.
- Why might a lender's figure differ from this calculator?
- Lenders round payments, apply interest daily or monthly, allow for the exact day of the month you pay and often quote a payment that steps up when a fixed rate ends. Treat this as a close estimate, not a quotation.
Also useful: stamp duty calculator, mortgage and protection services and our Doctors and Dentists hubs.
Want to know what this means for your plans?
An adviser can look at the wider picture, including lender criteria, affordability and protection.
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