Between 13.4 and 16.5 million

Determining the exact number of children living in poverty can depend on what Census calculation you go by. More than 16 million children, or roughly one in five, were living in poverty in 2011, according to the U.S. Census Bureau’s official poverty measure (pdf). That is higher than any other age group. Among 18- to 64-year-olds, the poverty rate was 13.7 percent, while among seniors the rate was 8.7 percent.

The Census Bureau’s official figures fail to paint a complete picture, though. The formula the government uses to calculate the poverty rate was designed in the 1960s, and does not account for expenses that are necessary to even hold a job — such as transportation costs and child care. Nor does the formula account for government programs for the needy, such as food stamps and the Earned Income Tax Credit.

When the Census Bureau factors in (pdf) those types of variables in a new experimental formula the number of children found to be living in poverty falls to 13.4 million.