Most people approach a mortgage backwards. They find a house they want, then wonder if they can afford it. The smarter move is to know your number before you walk into a single viewing.
The income multiple rule
UK lenders typically offer between 4x and 4.5x your annual gross salary. That's the starting point for most applications.
- £40,000 salary → borrow up to £160,000–£180,000
- £60,000 salary → borrow up to £240,000–£270,000
- £80,000 salary → borrow up to £320,000–£360,000
Some lenders — particularly for professionals like doctors, lawyers, and accountants — will stretch to 5x or 5.5x. That's not a rumour. It's a specific product category several high street lenders offer.
Your deposit changes everything
The loan-to-value ratio (LTV) is the percentage of the property price you're borrowing. A £200,000 house with a £20,000 deposit means an LTV of 90%.
The lower your LTV, the better your rate — and sometimes the more you can borrow. Getting from 90% to 85% LTV can drop your rate by 0.3–0.5%. On a £200,000 mortgage over 25 years, that's thousands.
What lenders actually test
The income multiple is just the headline. Behind it, lenders run an affordability assessment that looks at:
- Your monthly debt commitments (car finance, credit cards, student loan)
- Your living costs and dependents
- A stress test — can you afford repayments if rates hit 6–7%?
Two people on the same salary can get very different offers based on their outgoings. Someone with no debt and no dependents will almost always outborrow someone with a car on finance and two children.
Joint applications
If you're buying with a partner, most lenders combine both incomes and apply the same 4–4.5x multiple. Two salaries of £35,000 each gives a combined £70,000 — and a potential borrowing range of £280,000–£315,000.
Some lenders weight the higher earner's salary more heavily. Worth asking about when you compare deals.
Get your number before you start
Use the mortgage calculator to run the numbers on what your repayments would actually look like at different borrowing levels. Then you'll walk into every viewing knowing exactly where you stand.