This square footage calculator finds the area of a rectangle, circle or triangle in square feet, square meters, square yards and acres. Add a price per square foot or meter to estimate the cost of flooring, carpet, paint or sod.
Square footage formulas
- Rectangle: length × width
- Triangle: base × height ÷ 2
- Circle: π × diameter² ÷ 4
1 square meter = 10.764 square feet, 1 square yard = 9 square feet and 1 acre = 43,560 square feet.
Worked example
A 15 × 12 ft room is 180 sq ft, which is 16.72 m² or 20 square yards. Flooring at $5 per square foot would cost about $900 before waste and installation.
Frequently asked questions
How do I measure an irregular room?
Split it into rectangles and triangles, calculate each one, and add them together.
How do I convert inches to feet first?
Divide inches by 12. A wall that is 10 ft 6 in long is 10.5 ft.