How Mortgage Affordability Works in the UK
UK lenders use two key methods to assess how much you can borrow: the income multiple (how many times your salary they will lend) and an affordability assessment (whether you can afford the monthly repayments after all other costs).
The income multiple is the simpler of the two. Most mainstream lenders will advance up to 4.5× your annual income. On a joint application, this is based on the combined income of both applicants. Some lenders will stretch to 5× for higher earners or professionals.
The affordability assessment looks at your actual monthly cash flow — income after tax minus all outgoings, including the proposed mortgage payment. Lenders also stress-test affordability at higher interest rates to ensure you could still afford the mortgage if rates were to rise.
Affordability by Salary — Quick Reference
| Annual Income | At 4× Salary | At 4.5× Salary | At 5× Salary |
|---|---|---|---|
| £30,000 | £120,000 | £135,000 | £150,000 |
| £40,000 | £160,000 | £180,000 | £200,000 |
| £50,000 | £200,000 | £225,000 | £250,000 |
| £60,000 | £240,000 | £270,000 | £300,000 |
| £75,000 | £300,000 | £337,500 | £375,000 |
| £100,000 | £400,000 | £450,000 | £500,000 |
These are indicative figures based on income multiples only. Actual offers depend on lender assessment, credit history, deposit, and outgoings.