UK Mortgage Affordability Calculator

How to use this calculator

1. Enter your household income. Choose "Joint application" if a second applicant's income should count, and set the share of any variable income you want included.
2. Enter your total deposit and a buying-cost reserve — either a quick total or itemised costs such as Stamp Duty/Land Tax, legal fees and surveys — so the calculator can work out the deposit left toward a property price.
3. Enter your existing monthly commitments and essential household costs, either as a quick total or itemised.
4. Enter any owner-only monthly costs you expect, such as buildings insurance, a service charge or maintenance — without double counting a cost already entered above.
5. Set your mortgage rate, term, stress-test rate, indicative income multiple and monthly safety buffer.
6. Read the illustrative borrowing limit and property-price range below, and optionally test a specific property price.

Results update as you change any figure. Use Reset to return to the worked example.

What do I need to enter?

• Single applicant or Joint application — joint adds a second applicant's income. At least one basic income must be above zero.
• Basic annual income, Variable annual income and Variable income included — gross income before tax. Only the share of variable income you set, 0% to 100%, counts; variable income is optional and blank means 0.
• Total deposit available — the cash you have, before buying costs are set aside.
• Buying-cost reserve — a Quick total or Itemise costs (Stamp Duty/Land Tax allowance, legal/conveyancing, survey/valuation, mortgage arrangement/broker fees, Moving/setup and other buying costs), each a one-off amount. It is taken off your deposit.
• Existing monthly commitments — a Quick total or itemised personal loans, Car finance/lease, credit-card minimums, BNPL/catalogue, child maintenance, Student Loan repayments and other contractual commitments, each a monthly payment. Blank means 0.
• Essential monthly household costs — a Quick total or itemised food/household, utilities/basic heating, transport, Childcare/dependants, Insurance not entered elsewhere (not buildings insurance, which is an owner-only cost), Council Tax, essential medical/prescriptions and other essentials, each a monthly cost.
• Owner-only monthly costs — buildings insurance, service charge or ground rent, maintenance allowance and other costs. Enter Council Tax in only one place.
• Mortgage interest rate and Mortgage term — the rate is 0% or more; the term is a whole number of years from 1 to 40.
• Stress-test interest rate — must be equal to or higher than the mortgage rate.
• Indicative income multiple — above 0 and up to 10 times income.
• Monthly safety buffer — an amount, 0 or more, held back from your monthly budget.
• Property price to test — optional. Enter a price to see how it compares.

What do the results show?

• Illustrative borrowing limit — the lower of the income-multiple ceiling and the stress-rate payment ceiling.
• Illustrative property price — that limit plus the deposit left after the buying-cost reserve.
• Mortgage payment at current rate and Payment at stress rate— the monthly repayment on the limit at each rate.
• Borrowing calculation — usable income, the income multiple, the monthly payment budget and each ceiling.
• Deposit and property price — total deposit, reserve, usable deposit and illustrative loan to value.
• Monthly planning — what remains each month before and after the safety buffer, at both rates.
• Test your property price and Sensitivity — shown when you enter a price to test, and a comparison across rate scenarios.

How does this calculator work?

This calculator works out two independent borrowing ceilings and uses the lower of the two as your illustrative borrowing limit. The first ceiling applies your chosen income multiple to your usable annual household income. The second ceiling works out the largest loan that a standard repayment mortgage, at your stress-test rate and chosen term, could be repaid from your monthly payment budget — what is left of your gross monthly income after your entered commitments, essential costs, owner-only costs and safety buffer.

Your illustrative borrowing limit is the lower of the income-multiple ceiling and the stress-rate payment ceiling. Your illustrative property price adds your usable deposit — your total deposit minus any buying-cost reserve you set aside — to that borrowing limit. For example, with a single £60,000 basic income, no variable income, a £40,000 deposit, a £5,000 buying-cost reserve, £500 of monthly commitments, £1,500 of essential costs, £250 of owner-only costs, a 25-year term, a 5% mortgage rate, a 7% stress rate, a 4.5× income multiple and a £500 safety buffer, the monthly payment budget is £2,250 and the income-multiple ceiling is £270,000 — the calculator reports whichever of the income-multiple and stress-payment ceilings is lower as the illustrative borrowing limit, then adds the £35,000 usable deposit to reach an illustrative property price.

What does this calculator assume, and what are its limits?

• Income is gross — before tax, National Insurance, pension contributions, Student Loan repayments and other payroll deductions. For an after-tax estimate, see the UK Take-Home Pay Calculator.
• Every cost, rate, term and multiple in this illustration is a figure you entered yourself; none are looked up or verified. Once you have a price and rate in mind, see the Mortgage Repayment Calculator for the monthly payment and full amortisation schedule.
• This calculator does not calculate Stamp Duty Land Tax, other purchase taxes, or any location-specific rule automatically — see the UK Stamp Duty Calculator for that.
• It does not check, estimate or predict credit history, lender eligibility, product availability or mortgage approval.
• It does not forecast future interest rates, house prices or your income — the stress rate and income multiple are planning assumptions you choose, not a market prediction.
• This is not a mortgage offer, lending decision, affordability assessment, financial advice, mortgage advice, tax advice or legal advice. If you are still deciding whether to rent or buy at all, see the Rent vs Buy Calculator.

Important information

Important: This calculator is a planning illustration, not a mortgage offer, lending decision or affordability assessment. Mortgage lenders use their own criteria and may verify income, review credit commitments, assess household spending, consider future changes and test whether payments remain manageable if interest rates rise.

Frequently asked questions