Calculate the area of rectangles, circles, and triangles in square feet — plus automatic conversions to square yards, square meters, and acres. The starting point for flooring, paint, sod, and roofing estimates.
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How to use this calculator
- Choose your shape: rectangle, circle, or triangle.
- For rectangles: enter length and width.
- For circles: enter the diameter.
- For triangles: enter the base and height.
The math behind it
Rectangle: length × width. Circle: π × (diameter ÷ 2)². Triangle: ½ × base × height. Conversions: 1 sq yd = 9 sq ft, 1 sq m = 10.764 sq ft, 1 acre = 43,560 sq ft.
FAQs
How do I measure square footage of a room?
Measure the length and width of the room in feet and multiply. For L-shaped rooms, split them into rectangles, calculate each, and add the results.
How many square feet are in a square yard?
9. Carpet and flooring are often priced per square yard — divide your square footage by 9 to convert.