Mortgage Affordability Calculator
Enter your income, deposit, and monthly commitments to get a maximum borrowing estimate and the highest property price you could afford. Includes LTV, payment as a share of take-home, and a stress test at 3% higher rate. No email address needed. Nothing uploaded.
Your Finances
Affordability Estimate
Full breakdown
This is an estimate based on standard UK lender criteria (4.5× income multiple, 40% affordability threshold). Actual lender decisions vary. This is not financial advice. Consult an independent mortgage adviser.
Learn more: how this calculator works out what you can borrow
Two limits, and the smaller one wins
The tool works out two caps and uses the lower. The first is 4.5 times your combined income. The second is affordability: the loan whose monthly payment, at the rate and term you enter, equals 40% of your estimated take-home pay minus your existing monthly debts. The result tells you which one applied.
For a single earner on 50,000 at 4.5% over 25 years, the multiple caps the loan at 225,000. The payment is 1,251 a month, 38% of an estimated 3,293 take-home. Add 600 a month of debts and affordability takes over, cutting the figure to about 129,000.
The 40% is the tool's assumption, not a published rule. Real lenders use their own affordability models and also look at outgoings, dependants and credit history.
The take-home estimate
The tool estimates tax for each earner separately, then adds the two take-home figures. It uses the England, Wales and Northern Ireland bands on GOV.UK's income tax page: a 12,570 personal allowance, 20% up to 50,270, 40% to 125,140 and 45% above, with the allowance reduced by 1 for every 2 earned over 100,000. Employee National Insurance is 8% between 12,570 and 50,270 and 2% above, based on the GOV.UK rates.
It leaves out pension contributions, student loans and Scottish rates, so if you have any of these your real take-home will be lower. For two people each on 40,000, the tool works out 5,387 a month take-home in total.
The 4.5 multiple and the stress payment
The Bank of England's statement on the affordability test says the test was withdrawn from 1 August 2022, and that the loan-to-income limit stays. That limit applies to the number of mortgages a lender can make at 4.5 times income or more, so 4.5 is not a cap on any one borrower.
The tool also shows your payment at 3 percentage points above your rate. For the 225,000 example that is 1,663 a month against 1,251. This figure is for information and does not reduce the amount you can borrow. A lender's own stress test may.
FAQ
Why did the tool use the income multiple and not affordability?
It takes the lower of the two caps, and for your inputs the multiple came out lower. Large monthly debts make the affordability cap the smaller one instead.
Will a lender give me the same figure?
Not necessarily. Lenders run their own checks, and this is a rough estimate. Treat it as a starting point and speak to a mortgage adviser or lender. It is not financial advice.
Does a bigger deposit change my borrowing limit?
Not in this tool. Both caps depend on income, debts, rate and term, so the deposit only raises the property price you can afford (borrowing plus deposit) and lowers the loan-to-value ratio.