Fiscalgrove
Calculators

United Kingdom calculators

UK

Choose your market

Mortgage Affordability Calculator: How Much Can I Borrow?

Estimate how much you could borrow and how much mortgage you can afford, based on your income, deposit, and a lender-style affordability stress test.

£

Gross annual salary (before tax) or self-employed net profit.

£

Leave at £0 if you're applying alone.

£
x

Most mainstream lenders cap borrowing at 4-4.5x combined income; a few specialist lenders go up to 5-5.5x.

%

The quoted rate on the mortgage product you're considering.

years
pp

Percentage points lenders add to the quoted rate to check you could still afford payments if rates rose.

Estimated maximum property price£200,000.00
Total income used£40,000.00
Maximum loan£180,000.00
Monthly payment at 5.2%£1,073.34
Stress-tested payment at 8.20%£1,413.20What a lender checks you could still afford

How this calculator works

Rather than working forward from a mortgage amount, an affordability calculator works backwards from yourincome. UK lenders typically start with an income multiple — most commonly around 4 to 4.5× your gross annual income, occasionally higher for specific lenders or professions — and use that to set a maximum loan size:

Maximum loan = (your income + joint income) × income multiple

Add your deposit to the maximum loan and you get an estimated maximum property price. Lenders then run an affordability stress test: they recalculate your monthly payment as if your rate were several percentage points higher than the one quoted, to check you could still comfortably afford the mortgage if rates rose after completion. This calculator shows you both figures side by side — your payment at today's quoted rate, and the stress-tested payment a lender would actually check against your income and outgoings.

Worked example

Take a couple with a combined income of £65,000 (a £40,000 salary plus a £25,000 joint income), a £40,000 deposit, and a lender using the default 4.5× income multiple. Their maximum loan works out at £292,500, giving a maximum property price of around£332,500 once the deposit is added. At a 5.2% rate over a 25-year term, that loan costs roughly £1,744 a month. But the lender's stress test — adding a 3 percentage point margin to reach 8.2% — recalculates the payment at around £2,296 a month, which is the figure the lender actually checks against the couple's income and outgoings before approving the loan.

What affects your result

  • Income multiple — the biggest single lever. Moving from 4x to 4.5x income increases the maximum loan by an eighth; some specialist lenders offer up to 5-5.5x for certain professions or higher earners.
  • Joint income — adding a second applicant's income to a joint application increases the combined income the multiple is applied to, though the lender will also look at both applicants' outgoings and credit history.
  • Deposit size — a larger deposit doesn't change your maximum loan, but it does increase your maximum property price pound for pound, and can also unlock a lower-rate LTV tier.
  • Existing debts and outgoings — credit cards, loans, car finance, and childcare costs all reduce the amount a lender considers you able to afford, regardless of your income multiple.
  • Interest rate and stress-test margin — a higher quoted rate, or a lender that applies a bigger stress-test margin, increases the stress-tested payment relative to your income, which can reduce how much you're able to borrow in practice.

A note on accuracy

This calculator illustrates how a typical UK lender's income-based affordability assessment works, using editable, clearly labelled default assumptions (a 4.5× income multiple and a 3 percentage point stress-test margin) rather than hidden ones. It does not model a specific lender's full underwriting criteria, which also weighs your credit history, employment type, dependants, and detailed outgoings — your actual maximum loan from a real lender may be higher or lower than this estimate. For general guidance on mortgage affordability, seeMoneyHelperand the Financial Conduct Authority.

Frequently asked questions

How much can I borrow on a 40k salary?

On a £40,000 sole income with a typical 4.5x income multiple, most mainstream lenders would consider a maximum loan of around £180,000. Add a £20,000 deposit and you could be looking at a property price of roughly £200,000, giving a monthly repayment of around £1,073 at a 5.2% rate over 25 years — though your actual maximum will depend on the lender, your outgoings, credit history, and the interest rate offered. Use the calculator above with your own numbers for a personalised figure.

How much mortgage can I afford in the UK?

UK lenders typically cap borrowing at 4-4.5x your gross annual income (sole or joint), though a small number of specialist lenders go up to 5-5.5x for certain professions or high earners. On top of the income multiple, every lender runs an affordability assessment that also checks your outgoings, existing debts, dependants, and a 'stress test' — whether you could still afford payments if rates rose by a few percentage points above the quoted rate.

How many times my salary can I borrow for a mortgage?

Most mainstream UK lenders will lend up to 4-4.5 times your gross annual salary (or combined salaries for a joint application). A handful of lenders offer 5x, and in limited cases up to 5.5x, usually reserved for certain professions (like doctors or accountants) or higher earners with lower outgoings. The income multiple is only the starting point though — actual affordability also depends on your outgoings, credit commitments, and the stress-tested payment.

How big a mortgage can I get on a £30,000 salary?

On a £30,000 sole income at a 4.5x multiple, the starting point for maximum borrowing is around £135,000. With a £15,000 deposit added, that implies a maximum property price of roughly £150,000, and a monthly payment of around £805 at a 5.2% rate over 25 years. If you have a partner or joint applicant, adding their income to the calculation increases the maximum loan proportionally.

Does adding a second applicant increase how much I can borrow?

Yes — on a joint application, lenders normally apply the income multiple to your combined gross income, not just the higher earner's. For example, combining a £40,000 income with a £25,000 joint income gives a total of £65,000, which at 4.5x supports a maximum loan of around £292,500 — considerably more than either applicant could borrow alone. Bear in mind existing debts and outgoings for both applicants are also taken into account.

What is a mortgage affordability stress test?

It's a check lenders run to see whether you could still afford your mortgage payments if interest rates rose after you took out the loan. Since the Bank of England withdrew its mandatory stress-test rate in 2022, lenders now set their own approach — commonly testing affordability at your product's quoted rate plus a margin (often around 1-3 percentage points, sometimes more). This calculator lets you adjust that margin to see how sensitive your affordability is to future rate rises.

Related calculators

Mortgage Repayment CalculatorWork out the monthly cost once you know your loan amount.Loan-to-Value (LTV) CalculatorSee how your deposit affects your LTV and rate tier.Stamp Duty (SDLT) CalculatorEstimate the tax due on your target purchase price.