Your maximum mortgage isn't just your salary times a magic number, however much the headlines suggest otherwise. Lenders run a two-part test: an income multiple to set an opening ceiling, then an affordability assessment (stress-tested monthly payments against your monthly outgoings) to check you can genuinely handle the debt.
This guide covers both parts, works through the numbers, and shows you how to model your own position with the mortgage affordability calculator.
Not financial advice. Mortgage lending criteria vary significantly between lenders and change over time. Always speak to an independent mortgage adviser (FCA regulated) before making a purchase decision. Sources: FCA responsible lending rules (MCOB 11.6); Bank of England Financial Policy Committee withdrawal of the affordability test (2022) and LTI flow limit guidance (updated July 2025); individual lender criteria.
1. The income multiple: your starting ceiling
The go-to rule of thumb is 4 to 4.5 times gross annual income for a single applicant. For joint applications, lenders usually work off the combined income:
| Gross income | 4× | 4.5× | 5× |
|---|---|---|---|
| £35,000 | £140,000 | £157,500 | £175,000 |
| £50,000 | £200,000 | £225,000 | £250,000 |
| £75,000 | £300,000 | £337,500 | £375,000 |
| £100,000 | £400,000 | £450,000 | £500,000 |
| £60,000 joint (£35k + £25k) | £240,000 | £270,000 | £300,000 |
The Bank of England's Financial Policy Committee keeps lending above 4.5× income to around 15% of new residential mortgages across the market. Since July 2025 that 15% has been an aggregate limit for the market as a whole, rather than a hard cap on every individual lender, so lenders now have a little more room to stretch above 4.5×. It was never a personal cap, so borrowing above 4.5× is possible, just less common.
Professional and higher earner multiples
Some lenders offer higher income multiples to a select group:
| Who | Typical multiple |
|---|---|
| Standard applicant | 4 to 4.5× |
| High earners (often £75,000+ single, £100,000+ joint) | 5 to 5.5× |
| Defined professionals (doctors, dentists, solicitors, accountants, surveyors, architects) | 5 to 5.5× |
| Large deposit (25%+) or very low committed outgoings | Top of the lender's range |
A handful of schemes now stretch to 6× for borrowers who fit tight criteria, some first-time buyer products among them, but they remain the exception rather than the rule.
2. The affordability stress test
On top of the income multiple, lenders run a monthly affordability test at a stressed interest rate. The question they're really asking: could you still cope if rates went up?
From 1 August 2022 the Bank of England's Financial Policy Committee (FPC) withdrew the mandatory affordability test, the old rule that checked you at 3% above your reversion rate. Affordability is now judged under the FCA's responsible lending rules (MCOB 11.6), and lenders set their own stress policies. Most still stress at 2% to 3% above either:
- The reversion rate (standard variable rate), or
- The Bank of England base rate plus a margin
Following an FCA nudge, several big lenders trimmed their stress rates through 2025, which let many borrowers take on a fair bit more:
| Lender (2025) | Reported effect on borrowing |
|---|---|
| Santander (first to move) | £10,000 to £35,000 more |
| Nationwide | around £28,000 more on average |
| Lloyds / Halifax | around £38,000 more |
| HSBC / First Direct | around £39,000 more on average |
Worked example: a 5-year fix at 4.5% while the lender's SVR is 7.5%. They test you at the higher of the two figures:
| Component | Figure |
|---|---|
| Product (pay) rate | 4.5% |
| Lender SVR / reversion rate | 7.5% |
| Rate used for the stress test | 7.5% |
At the stress rate, the monthly repayment usually has to sit comfortably below your income. A common rule of thumb is the 35/45 guide:
| Guideline | Cap on the monthly mortgage payment |
|---|---|
| Share of gross monthly income | about 35% |
| Share of net (take-home) monthly income | about 45% |
These are budgeting rules of thumb, not the exact test any single lender uses. Each lender runs its own income-and-expenditure assessment, and the cut-off varies.
Free calculator
Mortgage Affordability Calculator
Enter your income, outgoings and deposit to see the maximum borrowing estimate with a stress test.
3. Loan-to-Value (LTV) and deposit
The Loan-to-Value ratio is the mortgage as a percentage of the property's value. The higher the LTV, the more risk the lender is carrying, so the rates tend to climb to match:
| LTV | Deposit | Rate tier |
|---|---|---|
| 95% | 5% | Highest rates; limited lenders |
| 90% | 10% | Better rate availability |
| 75% | 25% | Good mainstream rates |
| 60% | 40% | Best available rates |
For a property worth £300,000 with a 10% deposit (£30,000), you need a mortgage of £270,000 at 90% LTV.
Don't forget the other buying costs. These land on top of your deposit, so budget for them separately or they quietly eat into the deposit you can actually put down:
| Upfront cost | Typical 2026 range |
|---|---|
| Conveyancing (legal fees plus disbursements) | £1,000 to £2,500 |
| Survey (RICS Level 2 or 3) | £400 to £1,500 |
| Mortgage arrangement / product fee | £0 to £1,500 |
| Stamp duty (SDLT / LBTT / LTT) | See our stamp duty guide |
Leasehold and higher-value properties push the conveyancing and survey figures towards the top of those ranges.
4. How outgoings affect what you can borrow
Lenders weigh your committed monthly outgoings against your income. Here's how the usual suspects are treated:
| Outgoing | How lenders treat it |
|---|---|
| Loan and credit card repayments | Counted (the card minimum counts, not just what you choose to pay) |
| Car finance (PCP, HP, personal loan) | Counted in full |
| Student loan deductions | Counted; they show on payslips as a hard commitment |
| Child maintenance (court-ordered) | Counted |
| Childcare costs | Counted by some lenders, not all |
| Everyday discretionary spending (dining out, gym) | Usually not treated as a hard commitment |
Heavy outgoings can knock a real dent in your offer. Here's how a £400/month car finance payment can trim the borrowing of a lender working on a 4× multiple:
| Step | Figure |
|---|---|
| Monthly car finance | £400 |
| Annual commitment (£400 × 12) | £4,800 |
| Income equivalent removed at 4× (£4,800 × 4) | £19,200 |
Clearing the smaller debts before you apply can quietly lift your borrowing power.
5. Joint mortgages
On a joint mortgage, lenders add both incomes together. They also add both sets of committed outgoings, mind, so it cuts both ways. The income multiple then applies to the combined gross salary:
| Component | Figure |
|---|---|
| Applicant A income | £35,000 |
| Applicant B income | £30,000 |
| Combined gross income | £65,000 |
| Maximum at 4.5× | £292,500 |
Outgoings of £500/month between them would pull down the affordable repayment figure in the stress test, so that £292,500 ceiling is a starting point, not a promise.
Joint mortgages also mean joint liability: both of you are equally on the hook for the whole debt, not just your half.
Also check
Mortgage Repayment Calculator
Once you know your borrowing amount, calculate monthly repayments across different rates and terms, complete with a full amortisation schedule.
Related guides
- Stamp duty explained: SDLT, LBTT and LTT: stamp duty stacks onto your upfront buying costs
- How is take-home pay calculated?: your net income drives the affordability stress test