DIY CalculatorMeasure wall to wall at floor level, round up to the nearest inch, and leave out spaces you won’t cover (like a kitchen island for flooring).
Good to know
- Rectangle: length × width.
- Circle: 3.1416 × (diameter ÷ 2)².
- Triangle: base × height ÷ 2.
- Flooring: buy 5–10% more than the square footage for cuts.
Common sizes converted
| Size | Square feet | Square yards | Square meters | Acres |
|---|---|---|---|---|
| 10 × 10 ft | 100 | 11.11 | 9.29 | 0.002 |
| 12 × 12 ft | 144 | 16 | 13.38 | 0.003 |
| 12 × 15 ft | 180 | 20 | 16.72 | 0.004 |
| 15 × 20 ft | 300 | 33.33 | 27.87 | 0.007 |
| 20 × 25 ft | 500 | 55.56 | 46.45 | 0.011 |
| 50 × 100 ft | 5,000 | 556 | 465 | 0.115 |
| 100 × 200 ft | 20,000 | 2,222 | 1,858 | 0.459 |
How to use this calculator
- Measure the length and width (or the diameter of a round area). Use any unit — feet, inches, yards or meters.
- Split odd shapes into rectangles, circles and triangles, and add each one with “Add another area”.
- Optionally enter a price to estimate the cost.
Add this calculator to your website
Run a landscaping supply, garden center or DIY blog? Paste this code into your page to let visitors use the square footage calculator right there. It is free, has no ads, and resizes itself to fit.
More calculators
Frequently asked questions
How do I calculate the square footage of a room?
Multiply the length by the width in feet. A 12 ft × 15 ft room is 180 square feet. For odd shapes, split the room into rectangles and add them up.
How do I convert inches to square feet?
Multiply length × width in inches and divide by 144. A 48 × 36 inch rug is 1,728 ÷ 144 = 12 square feet.
How many square feet are in an acre?
43,560 square feet.