Mortgage Repayment Calculator
Work out your monthly mortgage payment, how much interest you'll pay over the full term, and what the payment would look like if rates rose by 3% (the affordability stress test lenders use).
Your mortgage
Show LTV (optional)
Year-by-year breakdown
| Year | Principal paid | Interest paid | Balance left |
|---|---|---|---|
| 1 | £5,567 | £14,567 | £274,433 |
| 2 | £5,867 | £14,268 | £268,566 |
| 3 | £6,182 | £13,952 | £262,384 |
| 4 | £6,515 | £13,620 | £255,869 |
| 5 | £6,865 | £13,269 | £249,003 |
| ... | |||
| 23 | £17,627 | £2,508 | £38,150 |
| 24 | £18,574 | £1,560 | £19,576 |
| 25 | £19,573 | £561 | £2 |
How this calculator works
We use the standard mortgage amortisation formula: each month a fixed payment is split between interest (charged on the remaining balance) and principal (which reduces the balance). Early years are interest-heavy, later years are principal-heavy, but the monthly payment stays the same.
The +3% stress test shows what your monthly payment would be if rates rose by 3% percentage points. This is the figure UK lenders typically use to check whether a borrower can still afford the mortgage in a higher-rate environment. It's a useful sense-check even if you're on a fixed deal today.
Interest-only mortgages charge only the monthly interest, with the full capital repaid at the end of the term (usually via an investment vehicle, the sale of another asset, or downsizing). Most residential mortgages are repayment (capital + interest), so leave the checkbox unticked for the standard case.
Pair this with our Affordability Calculator to see the max you could borrow, or the Stamp Duty Calculator for the tax due at purchase.
Indicative figures only. Actual mortgage offers depend on the lender's product range, your credit profile, LTV bands and the assessed value of the property. Use this as a planning guide, then get a Decision in Principle from a broker or lender for the real numbers.