Calculate UK repayment and interest-only mortgage payments.
A £300,000 property with a 10% deposit at 4.5% over 25 years costs £1,500.75 a month on a repayment mortgage. Interest-only on the same loan would be £1,012.50 a month.
In the UK you can choose a repayment mortgage, where each payment reduces the debt, or an interest-only mortgage, where you pay only the interest and must repay the capital at the end. Enter the property price, deposit, rate and term to compare the two.
Stamp Duty Land Tax (or LBTT in Scotland and LTT in Wales) is not included — check the current rates on GOV.UK. Rates change with the Bank of England base rate, so a fixed deal protects you for a set period. See the Mortgage Calculator for rupee-based loans.
The calculator applies the standard financial formulas step by step.
| Item | Amount |
|---|---|
| Price | £300,000.00 |
| Down payment | £30,000.00 |
| Loan amount | £270,000.00 |
| Monthly payment (principal + interest) | £1,500.75 |
| Total interest | £180,224.31 |
| Total of all payments | £450,224.31 |
| Time to pay off | 25 years |
| Term | 3.5% p.a. | 4.5% p.a. | 5.5% p.a. |
|---|---|---|---|
| 15 years | £1,930.18 | £2,065.48 | £2,206.13 |
| 20 years | £1,565.89 | £1,708.15 | £1,857.30 |
| 25 years | £1,351.68 | £1,500.75 | £1,658.04 |
| 30 years | £1,212.42 | £1,368.05 | £1,533.03 |
Repayment clears the debt by the end of the term. Interest-only has lower payments but leaves the full loan to repay at the end.
Typically 5–10% minimum; a larger deposit gives access to lower rates.
No. Stamp Duty Land Tax (England and Northern Ireland), LBTT (Scotland) or LTT (Wales) is a separate cost.
The mortgage as a percentage of the property value. Lower LTV usually means a lower interest rate.
Most lenders allow overpayments of up to 10% a year without early repayment charges during a fixed deal.
You move to the lender's standard variable rate unless you remortgage. Compare deals a few months ahead.
It uses the standard formula: repayment = P × r ÷ (1 − (1 + r)^−n) The full method and a worked example are shown on this page.
No. The calculator gives estimates for planning and learning. Real offers vary by lender, product and date, so confirm the details with your bank, lender or a qualified adviser before deciding.
Yes. The maths is identical in any currency; only the currency symbol shown in the results differs.
No. Everything is calculated in your browser and nothing you enter is uploaded or saved.
