On average, dwellings in Japan have 91.92 square meters (about 989 square feet) of floor space per household. The average for a family of three is 91.8 square meters (about 988 square feet), and that for a four-member household is 96.0 square meters (about 1033 square feet).
By number of rooms, the average for all households is 4.31. A three-member family has an average of 4.87 rooms, and a family of four has 5.03 rooms.
Six out of 10 Japanese live in single-family houses. The rest live in apartments and other multi-unit buildings.
One survey says that 80% of families with children have at least one room for the kids, and about 50% provide one room for each child. The average size of a kid's room is 10 square meters (around 108 square feet).