Square Footage Calculator
Calculate rectangular floor or project area instantly.
Project inputs
Enter your measurements. Results update automatically.
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See estimating toolsHow to calculate square footage
For a rectangular area, multiply the length in feet by the width in feet. The result is square feet. This calculator also converts the same area to square yards so you can use the number for flooring, rooms, decks, walls and other construction planning.
Square footage formula
Length × width = square feet. A 12-foot by 15-foot area is 180 square feet. For several rectangles, calculate each area separately and add the results.
Irregular spaces
Break an L-shaped or irregular project into simple rectangles. Calculate each section and add them together. Openings or areas that should not be included can be calculated separately and subtracted.
Where square footage is useful
Square footage is a starting point for estimating flooring, drywall, paintable surfaces, decking, roofing plan area and many other material takeoffs. Material coverage and waste are separate from the basic area calculation.
Common square footage questions
How many square feet are in a square yard?
One square yard equals 9 square feet.
Do I include waste in square footage?
Keep the measured area separate, then add the waste or extra-material allowance required for the specific material and layout.
Can I use inches?
This calculator uses feet. Convert inches to feet first by dividing inches by 12.