According to Apartment Therapy, three people can live in 600 square feet. Each person in an apartment needs 200 square feet, though Apartment Therapy argues that 450 square feet per person would be "more comfortable.
As of 2014, the average square footage for homes in the United States was 2,598 square feet, according to the U.S. Census Bureau. Apartment Therapy states that people who live in apartments require less space than those living in houses. They also argue that 200 square feet per person allows for living essentials, which include an adult-sized bed, a bathroom, an area for cooking and a sitting area.