Before you fall in love with a house, it pays to know the number that decides everything: how much a lender will actually let you borrow. It is rarely as much as people hope, and it is not a single figure — it flexes with your deposit, your debts and the lender's stress test. Get a realistic estimate first and you save yourself the heartbreak of viewing homes you can never finance. Here is how lenders work it out in 2025/26.
- Most lenders cap borrowing at around 4 to 4.5 times your annual income.
- They then run an affordability and stress test on your actual outgoings, which can lower that.
- Existing debts, credit commitments and childcare reduce how much you can borrow.
- A bigger deposit unlocks lower rates and sometimes more generous lending.
The starting point: the income multiple
The headline rule of thumb is the income multiple. Most lenders will advance roughly 4 to 4.5 times your gross annual income, though some go higher for strong applicants or specific schemes. For a single applicant earning £40,000:
At 4x income
£40,000 × 4 = £160,000.
At 4.5x income
£40,000 × 4.5 = £180,000.
Joint applicants combine incomes, so a couple earning £40,000 each could borrow toward £320,000–£360,000.
That gives a ballpark, but it is only the ceiling. The actual offer comes from the affordability assessment.
The affordability and stress test
Since the mortgage rules tightened after the financial crisis, lenders cannot just multiply your salary and lend. They must check you can afford the repayments — not only at today's rate, but at a higher stressed rate, to be sure you could cope if rates rose. They look at your real monthly picture:
- Your take-home pay.
- Committed outgoings: existing loans, credit cards, car finance, childcare.
- Living costs and the number of dependants.
If your outgoings are high relative to income, the amount you can borrow falls below the headline multiple. If you are debt-free with low commitments, you may reach or exceed it. Our mortgage affordability calculator applies this logic so you get a realistic figure, not just a multiple.
How debts shrink your borrowing
This is where would-be buyers get caught out. Every monthly commitment reduces what a lender will offer, often by far more than the payment itself. A £250-a-month car finance deal can cut your maximum mortgage by several thousand pounds, because the lender projects that commitment across the affordability calculation. Clearing or reducing debts before you apply can meaningfully increase what you can borrow.
Lenders see your credit commitments Outstanding loans, credit-card balances, car finance, buy-now-pay-later and even a large agreed overdraft all show on your credit file and feed the affordability test. Tidy your finances for three to six months before applying — pay down balances and avoid new credit.
The deposit changes everything
How much you put down does two things. First, it directly reduces how much you need to borrow. Second, it affects the loan-to-value (LTV) — the percentage of the property's value you are borrowing — which drives the interest rate you are offered:
| Deposit | LTV | Typical effect |
|---|---|---|
| 5% | 95% | Highest rates, fewer deals |
| 10% | 90% | Better choice and pricing |
| 25%+ | 75% or less | Lowest rates, widest choice |
A bigger deposit not only shrinks the loan but cuts the interest rate, lowering your monthly payment and improving affordability — a double benefit. The deposit calculator shows how long it takes to save to each LTV band, and the mortgage calculator turns a loan size into a monthly repayment.
A realistic worked example
A couple earning £35,000 and £30,000 — £65,000 combined — with a £30,000 deposit and no significant debts:
Income multiple
£65,000 × 4.5 = about £292,500 maximum loan.
Add the deposit
£292,500 + £30,000 = a property budget around £322,000.
Affordability check
with no debts and modest outgoings, they likely reach near the top of that range; with a car loan and childcare, expect it to come down.
It is a starting frame, not a promise — only a lender's full assessment (or a mortgage broker) gives a firm figure.
Frequently asked questions
Typically 4 to 4.5 times your gross annual income, though some lenders offer more for strong applicants or specific schemes. The final amount depends on the affordability assessment.
Yes. Joint applicants combine incomes, so two earners can usually borrow considerably more than one — subject to the same affordability and stress testing.
Existing debts, credit commitments, childcare and high living costs reduce affordability. The stress test also checks you could cope with higher interest rates, which can lower the figure.
A bigger deposit reduces the loan you need and lowers the loan-to-value, unlocking better interest rates and wider lender choice — which in turn improves affordability.
A broker can search the whole market, match you to lenders likely to accept you, and often secure better rates — particularly useful if your situation is non-standard.
Figures are 2025/26 estimates and illustrative only. Lending decisions depend on each lender's criteria and a full affordability assessment — treat calculator results as a guide and seek professional mortgage advice.