How to Calculate Square Footage
For a rectangular room, multiply length by width (both in feet). A 15ft × 12ft room is 180 square feet. For irregular shapes, divide the space into rectangles and triangles, calculate each separately, then add them together.
Always Add Waste Allowance
When buying flooring, tile, or carpet, add 10% extra to your calculated square footage for cuts, mistakes, and pattern matching. For diagonal installations or rooms with many angles, increase to 15%.
Frequently Asked Questions
Multiply length by width in feet. A 12ft × 15ft room is 180 square feet. For irregular rooms, divide into rectangles and triangles, then sum the areas.
Add 10% for waste from cuts and mistakes on standard installations. For diagonal patterns or complex room shapes, add 15% to be safe.
Divide square feet by 9 (since 1 square yard = 9 square feet). This is commonly needed for carpet, which is often priced per square yard.