Square Footage Calculator
Calculate the area of a rectangle, circle, or triangle in square feet, square meters, and acres. Useful for flooring, painting, landscaping, and real-estate measurements.
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Frequently asked questions
How do I measure a room accurately?
Measure wall-to-wall along the longest dimension first, then perpendicular wall-to-wall for the other dimension. Round to the nearest inch and convert to feet (12 inches = 1 ft, so 142 inches = 11.83 ft). Use a laser distance meter for accuracy beyond ~25 ft, where tape measures sag. Always measure twice — even pros find errors of 6+ inches on the first pass.
What's the difference between sqft and sqm?
Square feet is the US/UK standard; square meters is the metric standard used globally. Conversion: 1 sqft ≈ 0.0929 sqm, or 1 sqm ≈ 10.764 sqft. A 1,000 sqft house is ~93 sqm. Real estate listings, building codes, and HVAC sizing all use sqft in the US; almost everywhere else uses sqm.
How do I calculate area of an irregular shape?
Divide the space into rectangles, triangles, and circle segments, calculate each piece, then add them up. For an L-shaped room, split it into two rectangles at the inside corner. For a room with a curved bay window, calculate the rectangle plus the half-circle. Most odd shapes can be decomposed into 2-4 simple shapes you can measure directly.