Mortgage Affordability Calculator
How much you could borrow, and the property price you can reach
UK mortgage lenders typically lend between 4 and 4.5 times your annual gross income, adjusted for any existing monthly debt payments. Combine that with your deposit and you get the maximum property price you can realistically reach. This calculator gives you a fast estimate using standard lender rules.
Most lenders use 4 – 4.5× as their headline multiple. A few will go to 5× for higher earners or strong credit profiles. Pick the multiple that matches your situation; the result is an estimate, not an offer.
Breakdown
| Item | Amount |
|---|
Estimated SDLT at this price
Assumes a standard residential purchase. Switch buyer type on the main calculator for FTB or additional-property scenarios.
How this calculation works
Lenders cap your borrowing in two ways. Loan-to-income (LTI) caps the loan as a multiple of your gross annual income — usually 4 to 4.5 times for most applicants, occasionally up to 5× for higher earners. Debt-to-income (DTI) tests stress-test your monthly mortgage payment plus existing commitments against your monthly income, typically requiring it stays below 40–45% of net pay.
This calculator uses the simpler LTI approach with a haircut for existing debt: every £100 of monthly commitments reduces your headline LTI capacity by about £4,000 (because that £100 has to come out of the same income your mortgage payments would). It's a useful starting point, but the actual offer you get depends on the specific lender, the interest rate at the time, your credit file, and any quirks in your income (self-employment, bonuses, overtime).
Once you know your price ceiling
The next questions are usually: how much stamp duty will I pay, and what are my full costs to complete?
- Main SDLT calculator — band-by-band breakdown for any price and buyer type
- Moving costs calculator — SDLT plus solicitor, survey, removals, EPC, the lot
- First-time buyer calculator — if relief applies
A note on stress testing
Since 2014, UK lenders have been required to stress-test affordability against a higher interest rate than today's pay rate — typically the pay rate plus 1% or the lender's standard variable rate plus 1%, whichever is higher. Most lenders run this test internally before offering you a mortgage. The calculator above gives a headline figure assuming the loan passes the stress test; if rates rise after you apply, your headline LTI capacity may shrink before the application completes.
Sources
- FCA mortgage conduct of business rules
- Bank of England financial-stability publications (loan-to-income limits)
Calculation rules last reviewed: 8 May 2026.