Mortgage Affordability Calculator
Get an estimate of the maximum mortgage you may be able to borrow based on your income and deposit. The calculation uses a 4.5× income multiple and stress-tests affordability at your rate plus 3% — in line with typical lender criteria.
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Get free mortgage advice from HabitoHow mortgage affordability is assessed
Lenders in the UK assess affordability using two main tests: an income multiple test and a stress test. The income multiple limits the loan to a set multiple of your gross annual income — typically 4 to 4.5 times your income, though some lenders offer higher multiples in specific circumstances. The stress test checks that you could still afford repayments if interest rates were to rise, usually by 3 percentage points above the rate at which the mortgage is offered. This calculator uses the 4.5× income multiple and applies the standard 3% stress test to give a conservative estimate consistent with typical lender criteria.
The figure is an estimate only. Each lender applies its own affordability model, factoring in your existing financial commitments, credit history, employment type, and the property type. The maximum loan shown here may be higher or lower than what a specific lender offers you.
What affects how much you can borrow?
Beyond income multiples, lenders consider your monthly outgoings: existing loan and credit card payments, childcare costs, and other regular commitments reduce the amount you can borrow. Your credit score and history also influence lender decisions. Self-employed applicants typically need at least two years of accounts. Some lenders offer higher income multiples to applicants in certain professions or above specific income thresholds.
Frequently asked questions
Can I borrow more than 4.5 times my income?
Some lenders offer income multiples of 5× or higher, particularly for higher earners or professionals. The Financial Policy Committee cap limits the proportion of high loan-to-income mortgages a lender can write, so availability varies. A mortgage broker can identify lenders most likely to lend at a higher multiple based on your specific circumstances.
Does this calculator account for my existing debts?
No — the calculator uses only income and deposit. Existing credit commitments reduce the amount most lenders will offer in practice. If you have significant outstanding debts, the actual maximum mortgage may be lower than the figure shown.
What is the stress test rate and why does it matter?
Lenders are required to check you could afford repayments at a higher rate — typically the mortgage rate plus 3%. The monthly payment shown in your results is the stress-tested payment. This is why the monthly figure may look higher than the payment you would actually make at the headline rate you entered.
Is this estimate legally binding?
No. This calculator provides an estimate for guidance only. Only a formal mortgage offer from a lender constitutes a binding commitment to lend. A mortgage broker or lender will carry out a full affordability assessment based on your complete financial picture before issuing an offer.
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