One in four people could cope for less than a month if they relied solely on their savings to cover their outgoings, research suggests.
Some 26% of people surveyed across the UK said this, Yorkshire Building Society found.
One in six (15%) said they no savings at all.
People are often recommended to have savings put by which would cover at least three months of essential outgoings, in case they suffer an income shock such as a job loss.
Those earning relatively large amounts of cash were nearly as likely as lower earners to say they would run out of cash in three months.
Two in five (43%) people earning more than £100,000 say that without a job they would not be able to cope financially for longer than three months, compared with 48% of workers at the bottom end of the pay scale earning less than £15,000 a year.
Many people surveyed also said they feel under social pressure to spend.
Nearly half (49%) of those questioned feel pressure to spend as a result of what they see on social media, and a third (33%) feel they need to spend to keep up with family and friends.
Two-fifths (43%) regularly make impulse purchases they later regret – with 14% having spent more than £500 in the past year which they now wish they had saved instead, the poll of more than 2,000 people found.
Mike Regnier, chief executive of Yorkshire Building Society, said: “Our research highlights just how fragile many people’s finances are.
“While it can be hard for people to put money away, we mustn’t overlook the social pressures people come under to spend rather than save.”