UK mortgage repayment calculator
Enter the loan amount, annual interest rate and mortgage term in years. The calculator returns your estimated monthly payment, total amount repaid and total interest charged.
How UK mortgage repayments are calculated
UK repayment mortgage calculations use the standard annuity formula: each monthly payment covers both the interest accrued and a portion of the outstanding capital. In the early years, most of each payment goes towards interest; towards the end of the term, most of each payment reduces the capital balance.
For a £200,000 repayment mortgage at 5% over 25 years: monthly payment ≈ £1,169, total repaid ≈ £350,700, total interest ≈ £150,700. The same mortgage at 4% over 25 years: monthly payment ≈ £1,056, total interest ≈ £116,800 — a saving of approximately £33,900 in interest on a 1 percentage point rate difference.
Term length matters as much as rate: a £200,000 mortgage at 5% over 35 years costs approximately £1,012 per month — £157 less than the 25-year version — but generates approximately £224,000 in total interest, over £73,000 more. The trade-off between monthly affordability and total cost is the central decision when choosing a mortgage term.
After estimating repayments, use the mortgage affordability calculator to check whether the loan amount fits within standard lender income multiples.
UK mortgage rates: what to enter
If you have a mortgage offer, enter the exact rate stated in the offer. If you are planning ahead and do not yet have an offer, use the Bank of England's published average effective rates as a benchmark, or check live rates on a mortgage comparison site.
For stress testing — checking how repayments would change if rates rise — enter a higher rate (e.g. 6–7%) to see the upper range of affordability. This is particularly useful when planning around the end of a fixed-rate deal, where the reversion rate (SVR) is typically 2–4 percentage points higher than the initial rate.
Note on rate types: Fixed-rate mortgages maintain the same rate for an agreed period (usually 2 or 5 years). Tracker mortgages follow the Bank of England base rate plus a fixed margin. Standard variable rates (SVRs) are set by each lender and change at their discretion. This calculator works equally for all rate types.
Common UK mortgage repayment examples
| Loan amount | 4% / 25yr | 4.5% / 25yr | 5% / 25yr | 5% / 30yr |
|---|---|---|---|---|
| £150,000 | £792/mo | £833/mo | £877/mo | £805/mo |
| £200,000 | £1,056/mo | £1,111/mo | £1,169/mo | £1,074/mo |
| £250,000 | £1,320/mo | £1,389/mo | £1,461/mo | £1,342/mo |
| £300,000 | £1,584/mo | £1,667/mo | £1,754/mo | £1,610/mo |
| £400,000 | £2,111/mo | £2,222/mo | £2,338/mo | £2,147/mo |
All figures are estimates based on the standard annuity formula. Actual repayments depend on your lender's specific terms.
Frequently asked questions
What is the average UK mortgage repayment?
The average UK mortgage balance is approximately £170,000–£190,000. At 4.5% over 25 years, a £180,000 mortgage costs approximately £997 per month. Repayments vary significantly by loan size, rate and term — use the calculator above for your specific figures.
How much does a £200,000 mortgage cost per month?
A £200,000 repayment mortgage at 4.5% over 25 years costs approximately £1,111/month. At 5% it rises to approximately £1,169/month. At 5.5% approximately £1,228/month. For specific amounts, see also: £200k mortgage monthly payment UK.
What is the total interest on a UK mortgage?
A £200,000 mortgage at 4.5% over 25 years accumulates approximately £133,000 in total interest — meaning you repay about £333,000 in total. Extending the term to 35 years reduces monthly payments but adds approximately £63,000 more in interest.
Should I choose a 25-year or 30-year term?
A shorter term saves significant interest but increases the monthly payment. The right choice depends on your monthly budget and whether you intend to overpay. Overpaying a longer-term mortgage can achieve a similar interest saving to a shorter term with more payment flexibility. See our 25 vs 35 year mortgage comparison.
Does overpaying save money?
Yes — every pound of overpayment reduces the balance and the interest charged thereafter. Overpaying £200/month on a £200,000 mortgage at 4.5% saves approximately £30,000–£35,000 in interest and cuts around 5 years off the term. Most fixed-rate deals allow overpayments of up to 10%/year without an early repayment charge.
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Related guides
How much mortgage can I afford?
How lenders calculate affordability and what affects the limit
What happens when your fixed rate ends?
SVR, remortgaging options and avoiding reversion rate shock
25 vs 35 year mortgage comparison
Full cost comparison of different mortgage terms
Should I overpay my mortgage?
Interest saved vs putting money in savings
Important information
This calculator is for general information and planning purposes only. Results are estimates based on the standard annuity formula applied to your inputs. They do not constitute a mortgage offer, mortgage advice, or financial advice.
Actual mortgage repayments depend on your lender's specific terms, rate type, any fees added to the loan, and any changes to a variable or tracker rate after the initial deal period. The calculator does not account for arrangement fees, insurance, or any other mortgage-related costs.
Always seek independent advice from a qualified, FCA-regulated mortgage broker before making any mortgage decision. Read our full Disclaimer.
About the author
✓ Editorially reviewed — all Poqet guides are checked for factual accuracy before publication and updated when UK rates or legislation change. Editorial Policy