Mortgage affordability calculator
Most lenders estimate mortgage borrowing as a multiple of income: around 4.5 times gross annual income is typical, ranging from a cautious 4.0 times up to a stretch of 5.5 times for some borrowers. This calculator estimates the range you could borrow from your income, commitments and deposit for 2026/27.
How is the borrowing range worked out?
Lenders start from your gross annual income and apply a multiple. Around 4.5 times is common, so someone on £40,000 is often offered near £180,000. A cautious lender might sit closer to 4.0 times, while some stretch to 5.5 times for higher earners or specific schemes. That spread is why the result is a range, not one figure. Prospective buyers evaluating whether their borrowing limit makes homeownership more advantageous than tenancy can test both outcomes on the rent vs buy calculator.
Existing commitments narrow the range. Regular outgoings such as a car loan or childcare are treated as income you cannot put towards a mortgage, so the tool subtracts a year of those commitments before applying the multiple. On top of that, lenders stress-test the monthly payment against a higher rate to check you could still afford it if rates rose.
What would I borrow in a worked example?
A single applicant earning £40,000 with no commitments and a £25,000 deposit secures a typical loan of about £180,000, giving a purchase price near £205,000. The indicative monthly payment at 4.50% over 25 years is £1,000.50. Add a partner earning £30,000 and the assessed income jumps, lifting the whole range with it.
Common questions
How much can I borrow for a mortgage?
Most lenders cap the loan at about 4.5 times gross annual income, with a cautious floor near 4.0 times and a stretch of around 5.5 times for some borrowers or schemes. On a £40,000 income the typical figure is about £180,000, before your deposit is added.
Does my partner's income count?
Yes. On a joint application lenders usually add both incomes, then apply the multiple to the combined figure. Two incomes of £30,000 are treated much like one income of £60,000, which is why buying together lifts the borrowing ceiling.
How do existing debts affect it?
Regular committed outgoings such as loans, car finance and childcare reduce the income the multiple is applied to. This tool subtracts your monthly commitments over a year before working out the loan, which is roughly how a lender's affordability test treats them.
Is the income multiple a fixed rule?
No. It is a market rule of thumb, not a legal cap. Lenders also stress-test that you could still pay if rates rose, and factor in your credit record and spending. The real offer can be higher or lower than any multiple suggests.
What deposit do I need?
The bigger the deposit, the lower your loan-to-value and the better the rate. This tool adds your deposit to the loan to show the rough purchase price you could reach, but a 10% to 15% deposit is a common starting point.
How is the borrowing range worked out?
Assessable income is the combined income after existing monthly commitments are removed. That figure is then multiplied by three lender ranges: a cautious 4.0 times, a typical 4.5 times, and a stretch of 5.5 times for some lenders. The three results form the low, typical and high estimate shown above.
What would I borrow in a worked example?
A single applicant on £40,000 with no commitments and a £25,000 deposit reaches an estimated typical loan of £180,000, a purchase price near £205,000. The indicative monthly payment at 4.50% over 25 years is £1,000.50. Adding a partner's income raises the assessed income and lifts the whole range.
Sources & Rate Verification
Rates verified against official statutory guidance on 6 September 2026.