The average person would run out of money within 52 days if they were unable to work.
People have monthly outgoings of about £1,445, but they have an average of just £2,474 set aside in accessible savings, according to Yorkshire Building Society.
Its research found that 36% of people would run out of money within 11 days if they could not work, having less than £500 of savings.
To make matters worse, it found that nine out of 10 people had no form of income protection insurance to cover their bills if they were unable to work or lost their job.
A fifth of people admitted they had no idea how they would survive financially if they were unable to work, while others had unrealistic contingency plans.
About 19% of people said they would manage on state benefits, despite the fact of having weekly outgoings of around £334 and being likely to receive just £75.40 a week in benefits, although they may qualify for incapacity benefit on top of this.
A further 5% claimed they would sell their home to access money quickly, despite the fact that the state of the housing market makes it difficult to do this.
Among people who had some form of insurance, the majority had policies that would only pay out if they died, with 47% having life cover, while just 10% had income protection cover.
Yorkshire found that certain groups were more exposed than others, with divorced people the least likely to be able to cope if they lost their job, having savings that would last an average of just 35 days, while part-time workers would run out of money after 37 days.
Younger people also had lower levels of savings, with those aged 35-44 having money that would last for just 39 days if they were unable to work, while 16 to 24-year-olds could survive financially for just 41 days.
Tanya Jackson, corporate affairs manager at the building society, said: “In the current economic climate, this research paints an extremely alarming picture for those consumers without any protection products in place.
“Finances for many are already finely balanced due to the rising cost of living and the research reveals that both state benefits and savings are not viable options for the majority of consumers to rely upon for an adequate length of time.”
The research was supported by figures from Combined Insurance, which showed that 34% of people would run out of money after just 12 days if they were unable to work, while 52% would be able to survive for only 17 days.
It found that women were particularly vulnerable, with 30% having no savings at all, compared with just 21% of men.