The general rule is that you don’t want to spend more than 30% of your monthly salary on rent.
It’s an adage you might have heard from parents or grandparents — who, of course, bought their first home for a bargain you could only dream of.
But for Generation Rent, new data proves that the 30% rent rule is no longer financially feasible for many under-30s.
Comparing wage data from the Office For National Statistics (ONS) with the current average rents for rooms across the 50 cities with the highest rental supply, SpareRoom has debunked this myth once and for all.
According to the findings, the current pre-tax annual wage for 18 to 21-year-olds works out at an average of £22,001, which translates to a monthly pay packet of £1,833.
For those fitting into the 22 to 29 age bracket, this increases ever so slightly to £31,200 (£2,600 per month) — but it’s still not going far enough, with many young renters handing over almost half their monthly budget to their landlord.
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Remember the age-old myth plaguing Millennials and Gen Zs that just abandoning their monthly Netflix subscription and cutting down on innocent pick-me-ups like avocado toast would solve their problems and miraculously open up the path to homeownership? We’re not convinced.
Cross-referencing these salary figures with the famed ‘30% rule’ indicates that renters aged between 18 and 21 should allocate no more than £550, while those between 22 and 29 should spend a maximum of £780.
But this no longer holds up. In London alone, a city famously in the depths of both a rental and an affordable housing crisis, the average room rent in Q3 of 2025 (July, August, and September) was a startling £995.
SpareRoom’s equations have concluded that to be able to comfortably afford this, a renter would need to be taking home a pre-tax salary of £3,317 (AKA, £39,804 annually).
With those figures in mind, those earning a salary of £31,200 would end up in the red, spending 38% of their monthly outgoings on rent alone, while this figure increases to 45% for those on £26,600 and a harrowing 54% – more than half — for those bringing home £22,001.
The situation isn’t much better up in Bonnie Scotland, as in Edinburgh, the going rate now costs £887, which necessitates a salary of £35,480. But again, the 30% guideline is a mere daydream, as those earning £22,001 inevitably end up spending 48%.
It’s not all bad news, though, as the figures show that tenants living in Bradford (and earning £31,200) pay 18% of their monthly paycheck, lining landlords’ pockets with an average of £470.
‘This is more than a problem for renters’
Matt Hutchinson, director of SpareRoom, says: ‘In reality, the 30% affordability rule has been unrealistic for a long time. When rents are 40% or even 50% of income, as is more common today, affording them is challenging and saving for a deposit is out of the question.
‘This doesn’t just delay life plans. If you can’t meet unexpected costs outside of normal expenditure, then you’re more prone to debt. And when disposable income is severely reduced, there are knock-on effects for mental health and loneliness. So this is more than a problem for renters, it’s a problem for the economy and for society, too.’
It’s not just sky-high rents that are locking many under-30s out of moving into their own four walls: as Matt explains, not everyone is able to save a deposit equating to five weeks’ rent – and not every parent is able to bail out their child with a sneaky offering from the Bank of Mum and Dad.
He says: ‘The Renters’ Rights Bill seeks to ban the practice of asking for rent in advance – sometimes as much as 12 months’ worth – which will level the playing field.
‘Tenants will also be able to challenge annual rent increases, which can be reduced if the proposed rent is deemed to be above the market value. But that doesn’t tackle the biggest challenge of all, which is that market value rents are already way too high.’
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