Data suggests that the typical working-class family wouldn't make it in most big U.S. cities without taking on debt. In New York, for example, a working-class family would have to earn an extra $91,000 a year — above and beyond the parents' salaries — to enjoy a reasonable standard of living and without going into debt.

That's according to cost information site Howmuch.net, which first determined the cost of living in any given U.S. city for various types of households, from families with stay-at-home moms to middle-class couples.

For this report, the site focused on working-class families, which it defines as two adults and two children with a low-cost food plan and living in a 1,500 square-foot home. The two adults have incomes comparable to those of a home-appliance repairer and a manicurist.

In the map below, each bubble represents a city, and the color of each bubble represents how much money the typical working-class family would have left over after covering fixed costs such as housing and food.

"The darker the shade of red, the worse off you are," Howmuch.net explains. "The darker the shade of green, the better off you are. The size of the bubble also fits on a sliding scale — large and dark red means the city is totally unaffordable. Bigger dark green bubbles likewise indicate a city where the working class can get by."