Principal vs interest
Lifetime mortgage repayment
Principal$0
Interest$0
United Kingdom · GBP
UK mortgage calculator.
Estimate monthly repayments using UK mortgage terminology, costs, and conventions.
Balance over time
How your remaining principal declines
Mortgage repayment schedule
Annual summary including overpayments
| Year | Capital repaid | Interest | Overpayments | Total paid | Balance remaining |
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Compare deposit and mortgage term
See how monthly payments and total interest change across different deposits and terms.
Interest-rate stress test
See how your repayment and total interest could change if the mortgage rate rises.
0%+2.5%+5%
Stressed rate—
Stressed monthly repayment—
Monthly difference—
Additional total interest—
This scenario holds the higher rate constant for comparison. Your actual fixed, tracker, variable or follow-on rate may differ.
Mortgage overpayment calculator
Add regular overpayments or a lump sum to estimate the interest and time you could save.
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Total interest saved£0
Time savedNo change
New payoff date—
Balance comparison
Standard repaymentsWith overpayments
UK planning estimate only. Council tax, buildings insurance and service charges vary by nation, council and property. Product fees, affordability checks, purchase taxes and early-repayment charges are not included.
UK mortgage repayment guide
Calculate UK mortgage repayments and total interest
This UK mortgage calculator estimates the monthly capital-and-interest repayment for a residential or buy-to-let repayment mortgage. Enter the property price, deposit, mortgage term and annual interest rate to see the estimated loan, monthly housing cost, total interest and remaining balance over time.
The result is a planning illustration rather than a mortgage offer. A lender will assess income, regular spending, debts, credit history, deposit evidence and the property before deciding what it may lend.
How a repayment mortgage works
With a capital repayment mortgage, each monthly payment covers interest and repays part of the amount borrowed. The interest share is normally greatest near the start, while more capital is repaid later as the balance falls. By contrast, an interest-only mortgage normally requires a separate credible plan to repay the capital at the end of the term. MoneyHelper explains repayment and interest-only mortgages.
Deposit and loan-to-value
Your deposit reduces the amount borrowed. A larger deposit produces a lower loan-to-value ratio and may provide access to different mortgage products, but rates and eligibility still depend on the lender and application.
Mortgage term
A longer term normally reduces the required monthly repayment but keeps the balance outstanding for longer, which can increase lifetime interest. Compare 15-, 20-, 25- and 30-year examples in the table.
Fixed, tracker and variable rates
The calculator holds the entered rate constant. A fixed deal usually lasts for only part of the full mortgage term, while tracker and variable rates can change. Use the stress test to explore a higher-rate scenario.
Affordability checks
The repayment is not the same as the amount a lender will approve. UK lenders consider income and expenditure when checking whether repayments are affordable now and under relevant future circumstances. See the FCA’s mortgage affordability guidance.
Mortgage overpayments and lump sums
An overpayment reduces the capital earlier, so less future interest is charged if the rate and other assumptions remain unchanged. Enter a monthly amount, annual amount or one-off lump sum to compare the accelerated balance with the standard schedule.
Check your mortgage conditions first. Some products impose an early-repayment charge or limit penalty-free overpayments during a fixed or discounted period. MoneyHelper notes that overpayment allowances and charges vary, so the calculator does not deduct a generic penalty. Read MoneyHelper’s guidance on paying a mortgage early.
Costs not included in the mortgage repayment
The repayment result does not include arrangement or booking fees, valuation and legal costs, broker fees, moving expenses or purchase taxes. Property transaction tax also differs across the UK: SDLT applies in England and Northern Ireland, Land and Buildings Transaction Tax applies in Scotland, and Land Transaction Tax applies in Wales. Check the rules for the property’s nation and your buyer circumstances. Start with the official GOV.UK home-buying tax guide.
UK mortgage calculator questions
How is the monthly mortgage repayment calculated?
The calculator applies the entered annual interest rate over the selected term to the mortgage balance after the deposit. It assumes equal monthly capital-and-interest repayments and a rate that stays unchanged for the full term.
Does the calculation include council tax and insurance?
You can enter annual council tax, annual buildings insurance and a monthly service charge to see a broader housing-cost estimate. These costs do not reduce the mortgage balance.
Does this calculator include stamp duty?
No. Purchase tax depends on whether the property is in England, Northern Ireland, Scotland or Wales and on circumstances such as first-time-buyer status, additional-property ownership and residence. Use the relevant government calculator.
Can I calculate mortgage overpayments?
Yes. Add monthly, yearly or lump-sum overpayments to estimate a revised payoff date and potential interest saving. The result does not model early-repayment charges or product-specific limits.
Why might a lender’s repayment be different?
A lender may use a different rate, daily interest calculation, payment date, fee treatment or rounding method. The mortgage offer and illustration supplied by the lender are the authoritative figures.