Calculate the area of a room, a yard or any odd shape. Add as many pieces as you need and get the total in square feet.
Flooring, sod, sealing, cleaning…
Total area
180 sq ft
20 sq yd · 16.72 m² · 0.0041 acres
| Shape | Formula |
|---|---|
| Square or rectangle | length × width |
| Circle | 3.1416 × radius² |
| Triangle | base × height ÷ 2 |
| Trapezoid | (side a + side b) ÷ 2 × height |
| 1 square foot | 144 square inches |
| 1 square yard | 9 square feet |
| 1 square meter | 10.764 square feet |
| 1 acre | 43,560 square feet |
Square footage is the starting point for most home projects. Once you have it, use the flooring, tile, paint, mulch or air conditioner calculators.
For a rectangle, multiply length by width in feet. A 12 × 15 ft room is 180 sq ft. For a circle, multiply 3.1416 by the radius squared. For a triangle, multiply base by height and divide by 2.
Split it into two rectangles, calculate each one and add them. In the calculator, click "Add another area" for each piece.
Divide by 12. 6 inches is 0.5 ft and 9 inches is 0.75 ft. The calculator has separate feet and inches boxes, so you can type measurements as you read them off the tape.
An acre is 43,560 square feet. A square yard is 9 square feet and a square meter is about 10.764 square feet.
Last reviewed November 2, 2026.
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