How to Calculate Square Footage for Any Room or Space
Square footage is length times width. But real rooms have closets, bump-outs, and odd shapes. Here is how to handle them all.
Rectangle: Length × Width. A 12×14 room = 168 sq ft. Triangle: Base × Height / 2. A triangle with 10ft base and 8ft height = 40 sq ft. Circle: π × radius². A 10ft diameter circle = 3.14 × 25 = 78.5 sq ft. For odd-shaped rooms: divide into rectangles and triangles, calculate each, and add them together.
Common Calculations
A room with a closet: measure the main room and closet separately and add. A room with a bay window bump-out: measure the main rectangle plus the bump-out area. An L-shaped room: divide into two rectangles and add. Always measure in feet and inches, then convert inches to decimals (6 inches = 0.5 feet, 3 inches = 0.25 feet).
What You Need Square Footage For
Flooring: exact room dimensions. Paint: wall area (perimeter × height minus doors and windows). Tile: floor or wall area plus 10-15% waste. HVAC: total home square footage for sizing. Rent: price per square foot comparison between apartments. Real estate: price per square foot comparison between homes.