Square footage calculator
Find the area of a rectangle, triangle or circle in square feet, yards, metres and acres, with an optional cost.
About this calculator
Choose the shape, pick your unit, and enter the measurements. The area is shown in square feet, square yards, square metres, acres and hectares at once.
Use it for flooring, paint, turf, paving or a plot of land. Add several identical shapes with the quantity box, and a price per square foot to see the cost.
Measurements and terms explained
- Rectangle
- Area = length × width.
- Triangle
- Area = base × height ÷ 2. The height is the straight-line distance from the base to the opposite corner, not the slanted side.
- Circle
- Area = π × radius². Enter the diameter, which is the full width through the middle.
- Square foot (sq ft)
- A square 1 foot by 1 foot. 1 sq ft = 144 square inches.
- Square yard
- A square 3 feet by 3 feet, so 9 sq ft.
- Acre
- 43,560 sq ft, or about 4,047 m².
- Hectare
- 10,000 m², or about 2.47 acres.
Common questions
How do I measure an odd-shaped room?
Split it into rectangles and triangles, work out each area, and add them together.
How do I convert square feet to square metres?
Divide by 10.764. One square metre is about 10.76 square feet.
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