UK Mortgage Repayment Calculator
Estimate a capital-and-interest mortgage without inserting a hidden market rate. Compare a rate you enter, see the cost of adding a product fee, include regular home costs and test optional monthly overpayments.
Official sources reviewed 20 September 2026
Estimate your UK mortgage repayments
Your figures stay in this browser and are not saved or uploaded.
- Regional coverage
- England, NI, Scotland and Wales
- Mortgage modelled
- Capital and interest repayment
- Currency
- Pounds sterling (GBP)
Important notice
For general information and educational use only. This calculator is not financial advice, regulated mortgage advice, a personal recommendation, a mortgage illustration or European Standardised Information Sheet (ESIS), an agreement or decision in principle, an offer of credit, or a guarantee of affordability, eligibility or acceptance.
Do not apply for a mortgage, make an offer on a property, exchange contracts or make another financial commitment based only on this estimate. Confirm repayments, fees, charges, product conditions and affordability with the lender, and consider an FCA-regulated mortgage adviser and an appropriate legal or tax professional.
Your home may be repossessed if you do not keep up repayments on your mortgage.
What this calculator shows
Repayment and total interest
See the equal monthly repayment, first-payment split and total interest under a constant monthly-compounding rate.
Product-fee trade-off
Choose whether a lender product fee is paid upfront or added to the mortgage, then see the resulting balance and estimated interest on that fee.
Home budget and overpayments
Combine user-entered Council Tax, buildings insurance, service charges and maintenance, then estimate the effect of a regular overpayment.
Important limits
This version models one repayment mortgage with a constant annual rate, monthly compounding and equal monthly payments. It does not calculate how much a lender will offer, perform income or expenditure checks, search mortgage products, calculate APRC, reproduce an ESIS, value a property or assess creditworthiness. It excludes changing fixed, tracker or variable rates, interest-only mortgages, shared ownership, equity loans, offset accounts, payment holidays, arrears, cashback, early repayment charges, overpayment limits and lender-specific criteria.
Property transaction taxes are not included automatically. SDLT applies in England and Northern Ireland, while Scotland uses Land and Buildings Transaction Tax and Wales uses Land Transaction Tax. Buyer status, residence, additional-property rules and reliefs can change the amount. Use the relevant government calculator or a legal or tax professional, then enter the confirmed estimate under other upfront buying costs.
Which UK region this covers
The repayment calculation covers England, Northern Ireland, Scotland and Wales. Leaving location unspecified therefore uses the same UK-wide repayment formula.
Property transaction tax is different: England and Northern Ireland use SDLT, Scotland uses LBTT and Wales uses LTT. This calculator does not insert any of them automatically because buyer status, residence, additional properties, reliefs and cross-border transactions can change the result.
Published-calculator cross-check
For a £300,000 repayment mortgage at 5% over 25 years with no fee, this calculator gives £1,753.77 per month. Halifax displays £1,754 after rounding under its published assumptions of monthly interest, equal-length years and an unchanged rate. Lender totals can still differ because of daily interest, payment dates, fees and rounding.
Official UK references
- MoneyHelper: mortgage repayment calculator and estimate warning
- MoneyHelper: regulated mortgage advice and mortgage illustrations
- MoneyHelper: mortgage rates, overpayments and early repayment fees
- MoneyHelper: overpayment limits and early repayment charges
- FCA: lender affordability checks and mortgage support
- GOV.UK: SDLT scope and the separate Scottish and Welsh property taxes
JustFileKit is not affiliated with the UK Government, Money and Pensions Service, MoneyHelper, FCA or Halifax.
Frequently asked questions
Is this an affordability calculator or agreement in principle?
No. It only calculates repayments from the figures you enter. A lender checks income, spending, debts, credit information, the property and its own criteria before deciding how much it may lend.
Why can the lender's repayment differ?
A lender can calculate interest daily, use specific payment dates and rounding, charge fees, change a variable rate or apply product rules not represented here. Use the lender's mortgage illustration or ESIS for the actual offer.
Should I add the product fee to the mortgage?
Adding a fee reduces the cash needed upfront but normally means paying interest on it. This calculator shows that mathematical cost under one unchanged rate; it does not decide which product is suitable. Compare APRC, the illustration, incentives, fees and the period you expect to keep the mortgage.
Does the overpayment estimate include early repayment charges?
No. MoneyHelper and the FCA both warn that product terms can limit overpayments or impose an early repayment charge. Check the mortgage offer or ask the lender before paying extra.
Why is property purchase tax not calculated?
The UK does not have one national purchase-tax calculation. England and Northern Ireland use SDLT, Scotland uses LBTT and Wales uses LTT, with different reliefs and additional-property rules. A government calculator or conveyancer can provide the appropriate figure.