Nearly a third of the population of Britain is living on an "inadequate" income, according to research by the Joseph Rowntree Foundation (JRF).
In 2014-15, it said that 19 million people were living on less than the Minimum Income Standard (MIS). It said the problem was that household costs have been rising, while incomes have stagnated.
The government has already promised to tackle the issue, after Theresa May identified those "just about managing". It said it was taking "targeted action" to raise incomes.
Although the precise level depends on individual circumstances, a single person renting a flat outside London is said to need to earn at least £17,300 a year to reach the MIS.
For a working couple with two children, living in social housing, each of the individuals needs to earn £18,900 a year. In other words a couple could be earning £37,000 jointly, and still count as being below the MIS threshold.
Among the 19 million said to be below the MIS are six million children, representing 45% of all children in Britain. There are also 1.8 million pensioners, representing 14.6% of the age group.
