Calculate the area of rectangles, circles, and triangles in square feet. Perfect for flooring, painting, landscaping, and real estate measurements.
Last updated: March 2026 | By Patchworkr Team
Square footage (ft²) is a unit of area measurement representing a square that is one foot on each side. It's the standard unit for measuring floor space, land area, and surface area in the United States and many other countries.
Calculating square footage is essential for: estimating flooring materials (hardwood, tile, carpet), determining paint coverage needed, pricing real estate (homes are sold by square footage), planning landscaping projects, sizing HVAC systems, and calculating project costs.
For simple rectangles, the formula is Area = Length × Width. For circles, use Area = π × radius². For triangles, Area = (Base × Height) / 2. Always measure in the same units and convert the result as needed.
For a square (all sides equal), use the same formula: Side × Side.
The radius is half the diameter. A circle with 10ft diameter has a 5ft radius.
Height must be perpendicular (90°) to the base. A triangle is half the area of a rectangle with the same base and height.
Break the room into rectangles and triangles, measure each section separately, then add all the areas together. Or use a laser measure tool that can calculate irregular shapes automatically.
For flooring, yes—measure the usable floor space. For painting walls, subtract large openings like doors and windows. For HVAC and real estate, use gross square footage (don't subtract).
Add 10% for tile and hardwood (cutting waste), 5% for carpet and paint. Complex layouts with many cuts need more. It's cheaper to have extra than to run short mid-project.
They're the same! 'ft²' is the mathematical notation, 'sq ft' is spelled out. Both mean 'square feet.' Similarly, m² = sq m (square meters).
Multiply square feet by 0.0929. For example: 300 ft² × 0.0929 = 27.87 m². Or divide by 10.764. The metric system uses square meters (m²) as the standard unit.
US average: 2,000-2,500 ft² (185-230 m²). Small: 1,000-1,500 ft². Large: 3,000+ ft². Apartments: 700-1,200 ft². These vary significantly by region and country.
43,560 square feet = 1 acre. That's about 90% of a football field. A quarter-acre lot is 10,890 ft², roughly a 100ft × 110ft rectangle.
Yes! Measure wall length × height for each wall. Subtract large windows and doors. This gives paintable area. Most paint covers 350-400 ft² per gallon.
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