How to calculate square footage
Square footage is the area of a flat surface measured in square feet. For a rectangle, multiply the length by the width.
| Shape | Formula |
|---|---|
| Rectangle or square | length × width |
| Circle | 3.1416 × (diameter ÷ 2)² |
| Triangle | base × height ÷ 2 |
Worked example
A 12 × 10 ft bedroom is 120 sq ft. That is 13.33 square yards, or 11.15 m². A round patio 10 ft across is 3.1416 × 5² = 78.5 sq ft.
Measuring with feet and inches
Convert inches to decimal feet before you multiply: divide the inches by 12. A wall 10 ft 6 in long is 10.5 ft, and 11 ft 3 in is 11.25 ft.
| Inches | 3 | 4 | 6 | 8 | 9 |
|---|---|---|---|---|---|
| Feet | 0.25 | 0.33 | 0.5 | 0.67 | 0.75 |
Odd-shaped rooms
Break the space into rectangles, triangles and circles, measure each one, and add them together. For an L-shaped room, measure the two rectangles that make up the L. To remove an area, such as a kitchen island from a flooring order, calculate it separately and subtract it.
Unit conversions
| From | To | Multiply by |
|---|---|---|
| Square feet | Square metres | 0.0929 |
| Square metres | Square feet | 10.764 |
| Square feet | Square yards | ÷ 9 |
| Acres | Square feet | 43,560 |
| Hectares | Square metres | 10,000 |
Frequently asked questions
How do I calculate square feet of a room?
Measure the length and width in feet and multiply them. A 15 × 12 ft room is 180 square feet.
How many square feet are in a square metre?
One square metre equals 10.764 square feet. One square foot is 0.0929 square metres.
Is square footage the same as square feet?
Yes. Square footage is simply an area expressed in square feet.
How do I measure a room with a closet?
Measure the main room and the closet as separate rectangles and add their areas.
Last updated November 1, 2026.