UK Mortgage Repayment Calculator
Estimate the monthly payment, total interest and outstanding balance on a UK mortgage. Enter the loan amount, interest rate and term, and choose repayment or interest-only to see a full year-by-year breakdown.
Enter the mortgage loan amount in pounds.
| Year | Interest | Capital | Balance |
|---|---|---|---|
| 1 | £9,906.35 | £4,123.81 | £195,876.19 |
| 2 | £9,695.37 | £4,334.80 | £191,541.39 |
| 3 | £9,473.59 | £4,556.57 | £186,984.82 |
| 4 | £9,240.47 | £4,789.70 | £182,195.12 |
| 5 | £8,995.42 | £5,034.74 | £177,160.38 |
| 6 | £8,737.83 | £5,292.33 | £171,868.05 |
| 7 | £8,467.06 | £5,563.10 | £166,304.95 |
| 8 | £8,182.44 | £5,847.72 | £160,457.23 |
| 9 | £7,883.26 | £6,146.90 | £154,310.33 |
| 10 | £7,568.78 | £6,461.38 | £147,848.95 |
| 11 | £7,238.20 | £6,791.96 | £141,056.99 |
| 12 | £6,890.71 | £7,139.45 | £133,917.54 |
| 13 | £6,525.44 | £7,504.72 | £126,412.82 |
| 14 | £6,141.49 | £7,888.67 | £118,524.15 |
| 15 | £5,737.89 | £8,292.27 | £110,231.88 |
| 16 | £5,313.64 | £8,716.52 | £101,515.36 |
| 17 | £4,867.69 | £9,162.48 | £92,352.88 |
| 18 | £4,398.92 | £9,631.24 | £82,721.64 |
| 19 | £3,906.16 | £10,124.00 | £72,597.64 |
| 20 | £3,388.20 | £10,641.96 | £61,955.68 |
| 21 | £2,843.74 | £11,186.42 | £50,769.26 |
| 22 | £2,271.42 | £11,758.74 | £39,010.51 |
| 23 | £1,669.82 | £12,360.34 | £26,650.17 |
| 24 | £1,037.44 | £12,992.72 | £13,657.45 |
| 25 | £372.71 | £13,657.45 | £0.00 |
How it works
A UK mortgage payment has two components: interest and capital. On a repayment mortgage every monthly payment covers the interest due for the month plus a slice of the capital, so the balance gradually falls to zero over the term. On an interest-only mortgage you pay only the interest — the full loan is still outstanding at the end and must be repaid another way (a sale, a savings vehicle, or a switch to repayment).
The classic amortisation formula for a repayment mortgage is M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the loan, r is the monthly interest rate and n the number of monthly payments. A £200,000 loan over 25 years at 5% works out at roughly £1,169 a month, of which about £833 is interest in the very first month — a share that steadily shrinks over time.
This calculator assumes a single, constant interest rate for the whole term. In reality most UK mortgages start on a fixed or discounted rate for 2–5 years before reverting to the lender's standard variable rate, so your real monthly payment will change when your deal ends — that's also why a lender's own illustration may differ slightly from the figure here.
The figures here are the pure capital-and-interest payment. In real life you'll also budget for buildings insurance, life cover, arrangement fees, and on leasehold flats, service charges. Early repayment charges (ERCs) can apply if you overpay beyond your product's allowance or leave a deal early — see our mortgage overpayment calculator to see how extra payments could cut your interest and shorten your term.
Worked example
A £200,000 repayment mortgage over 25 years at a constant 5% works out at roughly £1,169 a month. Over the full term you'd repay around £350,700 in total, of which about £150,700 is interest. Switch the same loan to interest-only and the monthly payment drops to about £833 — but the full £200,000 capital is still owed at the end of the term.
Limitations of this calculator
- Assumes one constant interest rate for the entire term — real deals usually change rate after an initial fixed or discounted period.
- Excludes arrangement fees, valuation fees, buildings insurance, life cover and service charges.
- Does not model early repayment charges (ERCs) or overpayment allowances.
- Interest-only figures assume the full capital is repaid in one go at the end of the term.
Frequently asked questions
What's the difference between repayment and interest-only?
A repayment mortgage pays back both interest and capital each month, so the balance falls to zero by the end of the term. An interest-only mortgage pays only the interest — the full capital is still owed at the end and must be repaid separately.
How is my monthly payment calculated?
For a repayment mortgage: M = P × r × (1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly rate (annual ÷ 12) and n is the total number of monthly payments. For interest-only, monthly payment = P × r.
Why does most of my early payment go on interest?
Interest is charged on the outstanding balance, which is highest at the start. As you pay down capital, the interest portion falls and the capital portion rises — this is called amortisation.
Why does my lender's illustration differ from this figure?
Lender illustrations often include product fees added to the loan, different day-count conventions, or a variable/tracker rate that changes during the term. This calculator assumes one constant rate for the whole term, so treat it as an estimate rather than a binding quote.
Does this include fees or insurance?
No. This is the pure capital-and-interest payment. Arrangement fees, valuation fees, buildings insurance, life cover and any early repayment charges (ERCs) are all excluded.
Related calculators
Official sources
Figures on this page follow official UK government guidance. Rates last verified: 27 August 2026. See our data sources and calculation methodology.
Estimates for general guidance only — not personalised financial advice.