How to Calculate Square Footage for Any Room or Floor Plan
Square footage is the most common unit for measuring living space in the US. Whether you are listing a home for sale, planning a renovation, or figuring out how much flooring to buy, knowing how to measure accurately matters — and the process is simpler than most people think.
Rectangular and square rooms
Measure length and width in feet (round to the nearest half-foot). Multiply: Area = Length × Width. A room that is 14 feet long and 11 feet wide is 154 square feet. For multiple rooms, calculate each separately and sum the areas. Do not include closets or hallways unless you want total floor area.
L-shaped and irregular rooms
Break the space into rectangles. Measure and calculate each rectangle's area separately, then add them together. For an L-shaped room, draw a line to divide it into two rectangles, measure each, and sum the totals. The square footage calculator guides you through multi-shape floor plans step by step.
Square footage in real estate
Listed square footage typically means gross living area (GLA) — heated and finished living space above grade. Garages, unfinished basements, and covered porches are usually excluded, though practices vary. When comparing listings, confirm what is and is not included in the quoted figure.