Depending on class model used, the middle class may constitute anywhere from 25% to 66% of households.

It characterized the middle class as having a reasonable amount of discretionary income, so that they do not live from hand to mouth as the poor do, and defined it as beginning at the point where people have roughly a third of their income left for discretionary spending after paying for basic food and shelter. This allows people to buy consumer goods, improve their health care, and provide for their children's education.