How much house can I afford? (UK)

Lenders use the lower of the income-multiple cap and the affordability check, and the affordability check often binds first — especially with existing debt payments, council tax, bills, the High Income Child Benefit Charge if it applies, a shorter mortgage term, or a higher interest rate, all of which reduce how much monthly payment you can realistically stress-test for.

That's genuinely how HMRC calculates it — the charge is based on whichever partner has the higher individual "adjusted net income" (broadly, salary), not your household income added together. Two couples earning £45,000 each (£90,000 combined) pay nothing, while a couple where one earns £65,000 and the other £25,000 (£90,000 combined) faces a real charge — because it's about one person's income crossing £60,000, not the household total.

It checks you could still afford payments if rates rose after you borrowed. The Bank of England had a single mandated stress-test margin (rate + 3 percentage points) until it withdrew that rule in August 2022 — lenders now set their own margin under the FCA's broader affordability rules, typically somewhere around +1 to +3 percentage points, sometimes less for longer fixed-rate deals. That's why the uplift here is adjustable rather than fixed; the default (+2pp) is a reasonable middle estimate, not a rule. Your actual estimated monthly repayment (shown separately) always uses your real input rate, not the stressed one.

It covers your deposit plus property tax, which are the two largest upfront costs. It doesn't include solicitor/legal fees, survey costs, mortgage arrangement fees, or moving costs — budget a few thousand pounds extra for those depending on the property.

It's a simplified like-for-like comparison using fixed assumptions (3% rent growth, 3% home price growth, 5% return on cash if invested instead, 1%/year maintenance) — real outcomes depend heavily on your local market and how those assumptions actually play out over your time horizon, so treat it as a starting point for the conversation, not a forecast.