People who live alone are more likely to be renting and feel less financially secure than couples without children, according to the Office for National Statistics (ONS).
Those living on their own spend an average of 92% of their disposable income, compared with two-adult households who spend only 83% of theirs, ONS analysis of people aged 25 to 64 found.
This research compared people living alone with those living together with another adult and did not include those living with dependent children.
Those in the 25 to 64 age group who are living alone are less likely to own their home than couples, at 50% of households versus 75% respectively.
This means people living on their own have less opportunity to accumulate wealth through being home-owners, with some having benefited from rising property values.
Around half (51%) of those who live alone say they always or mostly have money left over at the end of the week or month, compared with nearly two-thirds (64%) of those who live with their partner.
People living on their own may also find it harder to build up savings.
More than a third (35%) of those living alone say they would not be able to make ends meet for more than a month, compared with 14% of couples without children.
The number of people living alone in the UK has been on the increase – and may partly be due to changing relationship patterns, such as people getting divorced, the report said.
The number of people living on their own went up by 16% to 7.7 million between 1997 and 2017, while the UK population increased by 13%.
By 2039, the number of one-person households is projected to rise to 10.7 million.
The rise in the number of people living alone is largely concentrated in older age groups.
While the number of people aged 25 to 44 living alone fell by 16% between 1997 and 2017, the number of 45 to 64-year-olds living on their own increased by 53% over the same period.
The ONS also said that, as well as the financial impact, when it comes to well-being, those living on their own report lower levels of happiness and higher levels of anxiety than those living together with a partner.
But it said: “While this may paint a negative picture for those living on their own, it is not clear that people’s living arrangements are directly associated with their personal well-being.
“It may be that some of characteristics that tend to go with living alone, like being divorced, or renting your home, may have more of an impact.”