Room Square Footage Calculator
Work out floor area for a plain rectangle, an L-shaped room, or a space you've broken into sections. Measure in feet, inches, meters, or centimeters — the result comes back in square feet, square yards, and square meters at once.
Measure the whole footprint as one rectangle, then the missing corner. Overall minus cutout is the floor.
Break any odd room into rectangles and add them up — set how many, then fill each.
Formula & how it works
Rectangle: area = length × width. L-shaped: area = overall − cutout. Multi-section: add each rectangle.
All inputs convert to feet first (1 in = 1/12 ft, 1 m ≈ 3.281 ft, 1 cm = 1/30.48 ft). Then 1 yd² = 9 ft² and 1 m² ≈ 10.764 ft².
Worked example
A 12 × 15 ft room is 180 ft² — that's 20 square yards and about 16.7 square meters, with a 54 ft perimeter. Make it L-shaped by removing an 8 × 5 ft corner from a 20 × 15 ft footprint: 300 − 40 = 260 ft². The L keeps the same 70 ft perimeter as its bounding rectangle.
Measuring rooms accurately
Break complex rooms into rectangles
Almost any floor plan, however irregular, can be split into rectangles that you measure separately and add together. Bump-outs, closets, and hallways each become their own section. The multi-section mode is built for exactly this — measure each piece, enter it as a section, and the areas sum automatically.
Feet-and-inches, cleanly
Measurements often land between feet, so either work in decimal feet (15 ft 6 in is 15.5 ft) or switch the whole calculator to inches and enter everything that way. Mixing the two is where errors creep in. If you measured in meters, leave it in meters — the result still comes back in square feet and yards for ordering US materials.
Area is the start, not the order
Square footage tells you the floor, but flooring, tile, and carpet all need extra for waste, cuts, and pattern matching, and carpet in particular depends on roll width. Use this number as the clean baseline, then add the right waste margin in the material-specific calculator.