Families have been hit by soaring transport and childcare costs, leaving them with a "monumental" task of trying to earn enough to get by, according to a new report.
Research by the Joseph Rowntree Foundation (JRF) found that a couple with two children had to earn £36,800 for an acceptable standard of living, up by almost a third since 2008.
The foundation said working families with children were being dealt a "damaging triple financial blow" of increased childcare costs, more expensive transport and cuts to tax credits.
Under a so-called minimum income standard worked out by the foundation, single people need to earn £16,400 a year, a lone parent with one child £23,900 and pensioner couples £231 a week.
A quarter of the UK population live below the standard - three million more than in 2008, two years before the general election.
Julia Unwin, chief executive of the JRF, said: "Families have a monumental task trying to earn enough to get by. Parents facing low wages and pressure on their working time have little prospect of finding the extra money they need to meet growing household expenses.
"This year's research shows that a dangerous cocktail of service cuts and stagnating incomes are being keenly felt by parents. Many working people face the risk of sliding into poverty. It illustrates how anti-poverty measures are needed to address not just people's incomes but also the costs that they face."
Donald Hirsch, co-author of the report, added: "People are being more modest in terms of what they think needs to be spent on participating in society, but this thrift has been outweighed by rising costs.
"Parents have not changed their view of most needs, including a nutritious diet and participation by children in activities vital for social inclusion. What has changed is the ability of many families to afford such essentials."
Oxfam's director of UK poverty, Chris Johnes, commented: "Yet again we are seeing evidence of working families being hit hardest by a perfect storm of soaring living costs and cuts to services and crucial support, like working tax credits.
"Millions of families are struggling to get by on dwindling incomes and even when both parents work full time they each need to earn 50% above the minimum wage, in order to provide a decent standard of living for their kids.
"These figures are a warning that we could see a generation of families that have to go without essentials."