Pew defined “Middle-income” Americans as adults whose annual household income is two-thirds to double the national median, after incomes have been adjusted for household size. In 2016, the national middle-income range was about $26,093 for single persons, $36,902 for couples, $45,195 for a family of three, $52,187 for a family of four, and $58,347 for a family of five. 

"Upper-income" is at least $78,281 for a single person, $110,706 for couples, $135,586 for families of three, $156,561 for a family of four, and $175,041 for a family of five. 

(Understanding that there are great variations in the cost of living from region to region, Pew has also included a calculator that takes location into account.)

Middle class households made slight gains between 2010 and 2016, with median income growing from $74,015 in 2010 to $78,442 in 2016, or roughly 6 percent. Upper-income households saw a median income gain from $172,152 to $187,872, or 9 percent. Lower-income households gained about 5 percent, $24,448 to $25,624. 

However Pew noted that middle class income is pretty much the same as it was in 2000, $78,056. It said that this is a reflection of lingering effects from recessions in 2001 and 2008. 

The most middle-income city in the U.S., with 65 percent of its population being middle class, was Sheboygan, WI. The most upper-income area was the San Jose-Sunnyvale-Santa Clara, Calif., region at 32 percent. The most lower income area was Laredo, Texas, at 49 percent.