What's the first thing most people do when thinking about getting a mortgage? Do some rough calculations based on your salary and a basic mortgage calculator. Well, most mortgage calculators lie to you – or at least, they don't tell you the whole story.
This post explains how UK mortgage lenders really calculate how much you can borrow, what changed when the Bank of England withdrew its affordability stress test, and what the maths looks like if you are the main earner or your income has changed after a career break. It’s for any woman working out her real borrowing power before she starts house hunting, not just the headline multiple a calculator might give you.
Most UK lenders will offer you between four and four and a half times your annual income as a starting point, though the exact figure depends on your circumstances and the lender's own policy. The Bank of England's Financial Policy Committee limits how many mortgages a lender can extend above 4.5 times income, capping this at 15% of new lending, which is why that figure remains the practical ceiling for most applicants (Bank of England, 2022).
Some lenders will stretch further for specific groups. HSBC, for example, offers first time buyers earning at least £35,000 solo or £55,000 jointly up to 5.5 times income where the loan to value is 90% or below. These enhanced multiples tend to sit with larger, well capitalised lenders and usually come with conditions attached, such as a minimum deposit or a professional qualification. They are the exception, not the rule, so it is worth treating any headline figure above five times income as something to verify with a specific lender rather than assume for yourself.
Income multiples are also only the first filter. Every lender then runs an affordability assessment on top, looking at what you actually spend each month before deciding what you can really borrow.
The Bank of England scrapped its formal affordability stress test from 1 August 2022, which is part of why some multiples have crept upward since. That test used to require lenders to check whether you could still afford repayments if your rate rose to your lender's standard variable rate plus 3%.
Removing it did not remove affordability checking altogether. The Financial Conduct Authority's mortgage conduct of business rules still require lenders to assess what happens if interest rates rise, using a minimum stress buffer of 100 basis points, and the loan to income flow limit described above still stands. In practice this means the maths is somewhat more generous than it was before 2022, but it is still built around your real spending, not just your salary. A calculator that only asks for your income and gives you a number is skipping a step that your actual lender will not skip.
If you are the main earner, or your income has changed, the picture gets more complicated
If you earn more than your partner, or your income dropped during a period of maternity leave or reduced hours, that shapes what a joint application adds up to more than most calculators let on. According to the Office for National Statistics, the gender pay gap for full time employees stood at 6.9% in April 2025, rising to 12.8% once part time work is included, and reaching 12.5% for women in their fifties specifically.
That gap matters here because a joint mortgage application is usually assessed on combined income, so a lower second income reduces total borrowing power more than people expect. It is also worth knowing that lenders vary in how they treat maternity or paternity pay, bonuses, overtime and self-employed income. Some will use your pre-leave salary if you are due to return to the same role and pay, others will only count what you are currently receiving, and self-employed applicants are typically asked for two to three years of accounts or tax returns rather than a single recent payslip. None of this is standardised, which is exactly why it is worth asking a specific lender or broker how they would treat your situation before you rule anything in or out.
Your income multiple is the headline figure, but deposit size, existing debt and monthly outgoings usually decide the real number more than your salary does. A larger deposit lowers your loan to value ratio, which typically unlocks better rates and sometimes a higher multiple. Existing credit commitments work the other way: most lenders want your total monthly debt, including the new mortgage, to sit under roughly 40 to 45% of your income, so a car finance agreement or a large credit card balance can reduce what you can borrow more than a modest difference in salary would.
Credit history plays a supporting role too. There is no single score that guarantees approval, but being on the electoral roll, keeping credit card balances well below their limit and avoiding several credit applications in a short space of time all help a lender see you as lower risk. None of this replaces the value of speaking to a broker who can see your whole financial picture, particularly if your income is mixed, recent, or about to change.
From Lucy, co-founder of Welleness
When I was working out what we could borrow for our own house, I remember being really blindsided when I spoke to a mortgage broker – my rough calculations were completely different from the reality of what we could actually borrow. I'd used a calculator, but hadn't understood the nuances of our situation.
What surprised me most was how differently our two incomes were treated once children were in the picture. My income had dipped during maternity leave and I had gone part time for a while afterwards, and I had to ask, more than once, exactly how that would be viewed. Nobody offers that information up front. You have to know to ask for it.
If you take one thing from this, let it be that your borrowing power is not a fixed fact about you. It is a calculation that depends on which lender you ask, what you tell them, and when you ask it. That is worth knowing before you fall in love with a house you have not actually confirmed you can afford.
Use a specific lender's own affordability calculator, such as Nationwide's or HSBC's, rather than a generic multiple calculator, since these reflect the lender's actual current policy rather than a rule of thumb.
If your income includes maternity or paternity pay, a recent career break, overtime, bonuses or self-employed earnings, call your bank or a broker directly and ask how that income will be assessed before you rule a property in or out.
Check your credit report for free through a service like Experian or ClearScore and register on the electoral roll if you have not already, since both can measurably affect your borrowing capacity within a few weeks.
Most lenders offer four to four and a half times your annual income, with some offering up to 5.5 times for specific groups such as first time buyers with higher incomes and smaller loan to value ratios.
It can, because lenders differ in whether they use your pre-leave salary or your current statutory pay. Ask the specific lender or your broker how they treat maternity or paternity income before you rely on a figure.
Yes, most joint applications combine both incomes and apply the lender's multiple to the total, though a significant gap between the two incomes can reduce total borrowing power more than a single-income estimate would suggest.
The Bank of England's specific stress test, which checked affordability against a rate three percentage points above the standard variable rate, was withdrawn in August 2022. Lenders are still required by the Financial Conduct Authority to build in a smaller buffer for potential rate rises.
If reading this has made you wonder what your own borrowing power actually looks like once your real income and outgoings are factored in, our free financial health check takes less than five minutes and gives you a clear picture across six areas of your financial life. It’s a great starting point for thinking about your finances holistically.
Here is what one customer said after using Welleness to get a clearer view of her finances before making a bigger decision.
"The app triggered the realisation that speaking to one person who can look at everything is more valuable, rather than individual specialists who you then have to re-educate on all your different bits." Agnes, Welleness user
You can also book a free call with a Welleness adviser at any time, simply drop us a message on WhatsApp.
This post is for informational purposes only and does not constitute financial advice. For guidance specific to your situation, speak to a regulated financial adviser.
Welleness is a women-led business on a mission to close the gender finance gap for good. We offer women a clear, confident and caring pathway to financial health – zero jargon, no pressure.
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