How much can I borrow for a mortgage in the UK?+
Most UK lenders lend 4–4.75x your gross annual income for a first-time buyer, sometimes up to 5x or more for higher earners or specific lender criteria. On a £40,000 salary that's typically £160,000–£200,000. Joint applications usually combine both incomes (sometimes capped at the higher earner + a percentage of the second). Use this calculator to see the realistic borrowing range for your specific income and outgoings.
What mortgage can I afford on my salary?+
Most UK lenders lend around 4 to 4.5 times your gross annual income, sometimes 4.75 times or more. At 4 to 4.5 times, £30,000 supports £120,000 to £135,000 and £50,000 supports £200,000 to £225,000. Your outgoings, credit history and the lender's stress test can move it either way.
How much mortgage can I afford based on a monthly payment?+
Work backwards from the payment. At 4.5% over 30 years, each £100 a month supports roughly £19,700 of borrowing, so £1,000 a month supports about £197,000. Higher rates or shorter terms support less.
How is mortgage affordability calculated by UK lenders?+
Three layers: an income multiple (typically 4–4.75x annual income), an affordability assessment that subtracts your committed monthly outgoings from your take-home pay, and a stress test that re-runs the monthly payment at a rate 1–3% higher than the actual product rate. You need to clear all three layers. The income multiple sets the ceiling; the affordability assessment and stress test set the floor below it.
What outgoings do mortgage lenders count against affordability?+
Credit commitments (loans, credit cards, car finance, store cards), regular monthly bills (council tax, utilities, broadband), childcare, child maintenance, and any regular household costs the lender can see on bank statements. Discretionary spending (gym, subscriptions, takeaways) generally isn't deducted but heavy or unusual spending patterns will be queried during underwriting.
What is the mortgage stress test in the UK?+
Lenders re-run the affordability calculation at a higher interest rate to check you could still afford the mortgage if rates rose. Until 2022 this was usually +3% above the product rate; in 2022 the Bank of England relaxed the mandatory stress test but most lenders still apply +1–3%. The stress test is why your borrowing figure feels lower than online calculators that don't apply one.
Does a bigger deposit increase how much I can borrow?+
Not directly — the borrowing figure is tied to income, not deposit. But a bigger deposit unlocks lower-LTV products with cheaper rates, which can make a higher total purchase price affordable. £200,000 mortgage at 4.5% costs £1,111/month; at 5.5% it's £1,228/month. The £117/month difference can shift what passes the affordability test materially.
Can I borrow more on a joint mortgage?+
Usually yes. Most UK lenders combine both incomes — sometimes adding them at full multiple, sometimes using the higher earner's full multiple plus a percentage of the second. Joint mortgages also share the affordability assessment, so both salaries reduce the deduction for committed outgoings. The result is typically 40-80% more borrowing capacity than a single applicant on the same income.
What's a good debt-to-income ratio for a UK mortgage?+
UK lenders don't publish a single DTI threshold like US lenders do — they use affordability assessments instead. As a working benchmark: total committed credit payments above 20% of gross monthly income typically reduce borrowing capacity meaningfully. Above 40% it gets hard to get a mortgage at all. The fastest way to increase borrowing capacity if you're tight is paying down existing credit, not increasing income.
Do lenders look at my credit score for affordability?+
Yes, but separately from affordability. Credit score affects which products you qualify for (and at what rate); affordability determines how much you can borrow. A poor credit score can shut you out of the cheapest products and push you toward specialist lenders with higher rates — which reduces the headline mortgage you can afford on the same income because the stress test bites harder.
How much should monthly mortgage payments be as a percentage of income?+
Common rules of thumb: keep total housing costs (mortgage + council tax + utilities + insurance) under 35% of gross income, or under 40% of net income. Lender stress tests bite around these thresholds. Going higher is technically possible but leaves limited buffer for rate rises, life changes, or unexpected expenses. The Readiness Summary tab in this tool checks where your numbers sit.
Is this calculator accurate for what a lender will actually offer?+
It's an indicative guide, not a quote. Real lender decisions involve property valuation, full credit check, employment verification, and underwriter discretion. For first-time buyers, calculator outputs are typically within 5–10% of a real Agreement in Principle. Take the calculator figure as a planning range, then get an AIP (free, same day with most lenders) for the actual number.