The average size of a room depends on its function or intended use, but in general, most rooms in American homes are about 100 square feet in size. Foyers and closets are much smaller than living rooms and garages, so the average size of individual rooms varies greatly.
Large living rooms usually have about 600 square feet of space, while smaller living rooms may only have 200 feet of space. Bedrooms average between 120 square feet and nearly 200 square feet, while kitchens average about 200 to 250 square feet. Small rooms, such as foyers, may only have 30 to 40 square feet of space.