American Middle Class is Shrinking - Pew Report - 2015

Pew starts with the U.S. median household income.

Then Pew defined "middle class" as households that had at least two-thirds of the median income, but no more than double that amount adjusted for household size.

Based on the above definition, for a household with three people, being middle class means making between about $42,000 and $126,000. If a  family of three makes less than $42,000, then it is  in the lower class. If  it makes more than $126,000, it is  in the upper class.

Based on this definition, middle in America is shrinking.