By CalculatorInn Team · Updated: 2026-03-22 · Free & accurate · Instant results
Calculate the area in square feet for rectangles, circles, and triangles. Useful for flooring, painting, landscaping, and real estate.
Interactive Square Footage Calculator
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Rectangle: L × W; Circle: π × r²; Triangle: ½ × base × height
For rectangles, multiply length by width. For circles, use the radius (length field) squared times π. For triangles, half the base times the height.
Measure the length and width of the room in feet, then multiply them together. For L-shaped rooms, divide into rectangles, calculate each, and add them together.
One acre equals 43,560 square feet. A football field (without end zones) is about 1.1 acres.
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