Mortgage Affordability in the UK
UK lenders start with an income multiple — typically 4 to 4.5 times your gross annual salary, or your combined salaries for a joint application. They then run an affordability assessment under FCA rules: committed spending such as loans, car finance, credit card balances and childcare reduces what they'll lend, and repayments are stress-tested at a higher rate.
This calculator takes a simple approach: it subtracts twelve months of your committed spending from your income and applies the multiple you choose. The result is a rough ceiling, not a lender decision — use it to set a budget, then get an agreement in principle.
On top of the deposit you'll usually need to pay Stamp Duty Land Tax (in England and Northern Ireland), plus solicitor's fees, searches, a survey and any lender arrangement fee. Since 1 April 2025 first-time buyers pay no SDLT up to £300,000 and 5% on the part between £300,001 and £500,000; above £500,000 the relief is lost entirely.
Frequently Asked Questions
How much mortgage can I get on £45,000?
At 4.5× with no other commitments, about £202,500. With a £30,000 deposit that suggests a budget of roughly £232,500. Lenders' own assessments may give more or less.
How much Stamp Duty will I pay?
On a £300,000 home a first-time buyer pays nothing; a home-mover pays £5,000 (2% of £125,000 plus 5% of £50,000); someone buying an additional property pays £20,000.
What deposit do I need?
Usually at least 5% of the price, though 10–25% gets access to cheaper rates. A larger deposit also reduces how much you need to borrow.
Should I choose a 25 or 35-year term?
A longer term lowers monthly repayments but means paying much more interest overall. You can usually overpay up to 10% a year on many deals to shorten the term.
Planning your finances for a mortgage application? Try our Take-Home Pay Calculator
Take-Home Calculator →