Square Footage Calculator
The square footage of any room or area, including L-shapes, circles and triangles, in sq ft, sq yd, m² and acres.
Area
120
sq ft
That's 13.33 sq yd or 11.15 m².
Same area in
- Square yards
- 13.33 sq yd
- Square meters
- 11.15 m²
- Acres
- 0.0028 acres
With extra
- Area to buy
- – sq ft
Cost
- Estimated cost
- –
How do I calculate square footage?
For a rectangle, multiply length × width, both in feet. A 12 × 10 ft room is 120 sq ft. For an L-shaped room, split it into two rectangles and add them. For a circle, multiply 3.1416 × radius × radius; for a triangle, base × height ÷ 2. Measurements in inches? Divide each by 12 first, or multiply them and divide the result by 144.
Worked example: a 12 × 10 ft bedroom
- Square feet: 12 × 10 = 120 sq ft.
- Square yards (how carpet is often priced): 120 ÷ 9 = 13.33 sq yd.
- Square meters: 120 × 0.0929 = 11.15 m².
- Buying flooring? Add 5 to 10% for cuts: about 126 to 132 sq ft.
Common room sizes
| Room | Square feet | Square meters |
|---|---|---|
| 10 × 10 ft | 100 | 9.29 |
| 10 × 12 ft | 120 | 11.15 |
| 12 × 12 ft | 144 | 13.38 |
| 12 × 15 ft | 180 | 16.72 |
| 15 × 20 ft | 300 | 27.87 |
| 20 × 20 ft (2-car garage) | 400 | 37.16 |
Measuring a room
- Measure wall to wall at floor level, in feet and inches. Round up to the next inch.
- Convert inches: 12 ft 6 in is 12.5 ft (6 ÷ 12 = 0.5). Or enter inches with the unit menu.
- L-shapes and odd rooms: split them into rectangles that don't overlap, then add the areas.
- Closets and alcoves: measure them separately and add them if you are buying flooring for them too.
Converting square footage
- Square yards: divide square feet by 9.
- Square meters: multiply square feet by 0.0929.
- Acres: divide square feet by 43,560.
- Square inches to square feet: divide by 144.
Frequently asked questions
How many square feet is a 12 × 12 room?
144 square feet (12 × 12).
How do I calculate the square footage of an L-shaped room?
Split it into two rectangles that don't overlap, multiply length × width for each, and add the results. For example, 20 × 12 ft plus 10 × 8 ft is 240 + 80 = 320 sq ft.
How do I convert square feet to square yards?
Divide by 9. For example, 180 sq ft ÷ 9 = 20 sq yd.
How many square feet are in an acre?
43,560 square feet.
How do I find the square footage of a circle?
Multiply 3.1416 by the radius squared (radius = half the diameter). A circle 10 ft across has a radius of 5 ft: 3.1416 × 5 × 5 = 78.5 sq ft.
How much extra flooring should I buy?
Usually 5 to 10% more than the room's square footage for cuts and mistakes, and more for diagonal layouts or many corners.
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Sources and method
- NIST Handbook 44, Appendix C — units of measurement — 1 sq ft = 0.09290304 m²; 1 acre = 43,560 sq ft
Last checked October 12, 2026. How we build and test every calculator: methodology.