How Much Can You Really Borrow? UK Mortgage Affordability in 2026

Every first-time buyer has heard the rule: you can borrow 4 to 4.5 times your salary. On the UK median gross annual salary of £39,039, that implies a solo borrower could get £156,000 to £175,000. A joint application on two median salaries? Somewhere around £312,000 to £351,000.

Those numbers are fiction. Or rather, they're a ceiling that almost nobody reaches.

The income multiple is where the conversation starts, not where it ends. Lenders run your application through an affordability model that accounts for every regular outgoing: childcare, car finance, credit card minimums, student loan repayments, even your monthly gym membership. Two applicants earning identical salaries will get wildly different offers depending on their committed spending.

Some specialist lenders — Habito, Darlington Building Society — advertise multiples up to 5.5x for professionals like doctors and solicitors. But these come with conditions: higher deposits, specific career trajectories, and they won't suit most borrowers. For the median buyer, plan on 4x to 4.25x after deductions.

Since 2014, the FCA's Mortgage Market Review has required lenders to stress-test every application. The question isn't whether you can afford today's rate — it's whether you could still pay if rates jumped.

Most lenders stress at their standard variable rate (SVR) plus 1-2%, or a floor rate of around 6-7%. With the base rate at 3.75% and typical SVRs sitting at 6.5-7.5%, the stress test effectively asks: could you keep paying if your monthly bill rose by 40-60%?

Here's a concrete example. A £250,000 mortgage at 4.2% over 25 years costs £1,349 per month. Stress-tested at 7%, that becomes £1,767. The lender needs to see that £1,767 fits within your budget after all other commitments. If it doesn't, they'll offer you less — not reject you outright.

The gap between those two bars is why so many buyers feel the system is rigged. You could comfortably afford the real payment but fail the hypothetical one. The stress test exists for good reason — the 2008 crash proved that — but it creates genuine frustration when rates are falling and affordability is improving in practice.

The FCA's responsible lending rules require lenders to assess whether you can afford repayments not just at the initial rate, but at a stress rate typically 3 percentage points above the revert rate. This is why your maximum borrowing can feel frustratingly low even when your income seems sufficient.

Your deposit size doesn't just determine how much you need to borrow. It fundamentally changes the rate you'll be offered and therefore how much a lender will approve.

At 95% loan-to-value (LTV), typical rates in March 2026 sit around 5.0-5.5%. Drop to 90% LTV and you're looking at 4.3-4.7%. Hit 75% LTV and rates fall to 3.8-4.2%. On a £250,000 property, the difference between a 5% and 25% deposit translates to roughly £200 per month in repayments — and that £200 feeds directly back into affordability calculations, potentially unlocking a higher borrowing amount.

For a couple on median salaries with no other debts, the approximate maximum borrowing looks like this:

These are illustrative — every lender calculates differently — but the pattern holds. The jump from 5% to 10% deposit unlocks significantly more borrowing capacity, not just because you need less mortgage, but because the lower rate changes the stress-test arithmetic.

Three things destroy mortgage affordability faster than anything else:

Student loan repayments. Plan 2 borrowers repay 9% of everything earned above £27,295. On a £39,000 salary, that's £87 per month the lender deducts before running affordability. Plan 5 borrowers (post-2023 starters) have a lower threshold of £25,000. Joint applicants both carrying student loans lose £150-200 per month of borrowing capacity — equivalent to roughly £30,000-40,000 less mortgage.

Car finance. A £300/month PCP deal wipes approximately £55,000-65,000 off your maximum mortgage. If you're six months from the end of a PCP contract, some lenders will disregard it. Most won't.

Credit card debt. Lenders typically assume 3-5% of your outstanding balance as a monthly commitment, even if you pay in full each month. A £5,000 credit card limit (not balance — limit) could cost you £10,000-15,000 in borrowing capacity with stricter lenders.

What doesn't matter as much as people think? Savings beyond your deposit. Having £30,000 in savings versus £5,000 in savings (assuming the same deposit) barely moves the dial. Affordability is an income-and-commitments calculation, not a wealth assessment. Your ISA balance is irrelevant to the affordability model.

Start 6 months before you apply. Close unused credit cards — the available limits count against you even if the balance is zero. Clear or reduce any revolving debt. If a car finance deal ends within 3-6 months, ask your broker whether the lender will disregard it.

Get a Decision in Principle (DIP) from 2-3 lenders before house-hunting. A DIP runs a soft credit check and tells you exactly what that lender will offer. They vary more than you'd expect — I've seen £30,000 differences between high-street banks on identical applications.

Consider a longer term. A 35-year mortgage versus 25-year reduces monthly payments by roughly 15%, which can unlock significantly higher borrowing. You'll pay more interest overall, but you can always overpay later to shorten the term. Read our guide on whether overpaying makes sense in the current environment.

Broker versus direct? Use a broker. Whole-of-market brokers access deals from 80+ lenders, including building societies and specialist lenders that don't appear on comparison sites. Some lenders — Metro Bank, Furness Building Society — use manual underwriting that considers your full picture rather than an algorithmic score. A broker knows which ones to approach for your specific circumstances.

Finally, if you're a first-time buyer, factor in stamp duty relief. You pay zero SDLT on the first £300,000, and 5% on the portion between £300,001 and £500,000. That saving — up to £10,000 on a £500,000 property — is cash you can redirect toward a larger deposit, which in turn improves your rate and affordability.

For more on the full mortgage landscape, see our UK mortgage guide.

For a step-by-step guide to the buying process, see our first-time buyer mortgage guide. And if you're saving for a deposit, a Lifetime ISA adds a 25% government bonus on savings up to £4,000 per year.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.