Mortgage Affordability Calculator

UK mortgage lenders typically offer 4 to 4.5 times your annual income, though some may stretch to 5.5 times for high earners with minimal outgoings. Affordability is assessed not just on income multiples but also on your ability to meet payments if interest rates rise.

Lenders apply a stress test, checking whether you could afford payments at a rate typically 3% above the product rate (or the lender's SVR, whichever is higher). This explains why you may be offered less than the headline income multiple suggests.

Joint applications combine both applicants' incomes. Existing debts (loans, credit cards, car finance) reduce the amount you can borrow. This calculator factors in your income, deposit, existing commitments and current rates to estimate your borrowing capacity.

How lenders calculate maximum borrowing. UK lenders typically use 4-4.5× annual income as the headline multiplier, but the actual offer depends on detailed affordability assessment: monthly outgoings (council tax, utilities, food, transport, childcare), existing debts (loans, credit cards), number of dependants, and credit score. A single person on £40k might be offered £160-180k. A couple jointly earning £70k might be offered £315-385k. Self-employed need 2-3 years of accounts with consistent profits.

Stress testing — the hidden hurdle. Since the 2014 Mortgage Market Review, lenders must stress-test borrowers' ability to repay at a rate 3% above the lender's Standard Variable Rate (typically 7-8% in 2026). Even if your actual rate is 4.5%, the lender checks you could afford payments at 7.5%. This is why borrowers can be offered less than the 4.5× multiplier suggests. The 'stress rate' is meant to protect against future rate rises and is reviewed quarterly by the Bank of England's Financial Policy Committee.

Joint mortgages and tenancy types. Joint applicants pool incomes — lenders typically use 100% of both salaries. Joint tenancy (most common for couples): both own 100% jointly, automatic right of survivorship. Tenants in common: separate shares (e.g. 60/40), each share can be willed independently — useful for unmarried couples and second marriages. Some lenders allow up to 4 applicants on one mortgage (e.g. parents + 2 children), and 'guarantor' mortgages where parents back the loan without ownership.

Boosting your borrowing power. (1) Pay down credit cards and overdrafts — outstanding balances reduce maximum borrowing pound-for-pound; (2) Defer non-essential car finance until after the mortgage; (3) Improve credit score (electoral roll, reduce credit utilisation, no recent applications); (4) Consider a 'professional mortgage' if you're a doctor/lawyer/accountant — some lenders offer 5-5.5× income for these; (5) Build a longer deposit — 25% LTV unlocks the best rates and stretches affordability.

How lenders calculate max borrowing. UK standard: 4-4.5x annual income (4.5x joint income common). Self-employed: 2-3 years' accounts averaged. Lenders apply detailed affordability assessment: monthly outgoings, existing debts, dependants, credit score, profession. A single person on £40k might get £160-£180k. Couple on £70k joint: £315-£385k. Professional mortgages (doctor/lawyer/accountant): 5-5.5x available from some lenders.

FCA stress test rules. Since 2014 Mortgage Market Review, lenders must test affordability at lender's SVR + 3% (typically 7-8% in 2026). Even if your fix rate is 4.5%, lender checks payments at 7.5%. This is why many borrowers are offered LESS than the 4.5x multiplier suggests. Stress rate reviewed quarterly by Bank of England's Financial Policy Committee.

Boosting your borrowing power. (1) Pay down credit cards — outstanding balances reduce max borrowing pound-for-pound; (2) Defer non-essential car finance until after mortgage; (3) Improve credit score: electoral roll, low credit utilisation, no recent applications; (4) Professional mortgage if eligible (doctor/lawyer/etc); (5) Larger deposit unlocks better rates and bigger multiples (25%+ LTV = best rates); (6) Joint application — pool incomes.

Hidden affordability traps. Childcare costs reduce affordability significantly — £1,500/month nursery = ~£200k less mortgage. New car on PCP £400/month = £55-£70k less mortgage. Long commute costs (rail season ticket £6k/year). Pet costs (£100/month included by many lenders). Lenders increasingly use Open Banking to verify spending — manually downloaded statements no longer trusted. Clean up spending 3-6 months before applying — fewer takeaways, no betting, no payday loans.