Calculate area in square feet, square yards, and acres for rectangles, triangles, circles, and L-shaped areas. Fast, accurate, no account needed.
Total stations and GPS rovers make area measurement fast and accurate for takeoff and layout. Shop survey equipment at Express Tools.
Shop Express Tools →Square footage = Length (ft) × Width (ft) for rectangles. For a triangle: 0.5 × Base × Height. For a circle: π × radius². For L-shapes: split into two rectangles and add the areas together. There are 9 sq ft in a square yard and 43,560 sq ft in an acre.
Square footage is the most common area measurement used in U.S. construction. Flooring, roofing, siding, and paint are all priced and ordered by the square foot. Carpet and some flooring materials are sold by the square yard (divide SF by 9). Land and site work is often expressed in acres for large areas. Concrete flatwork is sometimes quoted in square yards — a 1,000 SF slab is approximately 111 SY. Knowing which unit your supplier uses prevents costly mistakes on material orders.
| Space / Item | Typical Square Footage | Notes |
|---|---|---|
| Parking space | 162 sq ft (9×18) | Standard stall; handicap stalls wider |
| One-car garage | 200–400 sq ft | Single door 10×20 typical |
| Standard room | 120–250 sq ft | Bedroom 10×12 to 12×15 |
| Ranch home (1 story) | 1,200–2,000 sq ft | Varies by region and era |
| Football field | 48,000 sq ft | 1.10 acres including end zones |
| Basketball court (NBA) | 4,700 sq ft | 94 × 50 ft |
| Half-acre lot | 21,780 sq ft | ~132 × 165 ft typical |
| 1-acre square lot | 43,560 sq ft | 208.7 × 208.7 ft |
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Start free trialFor a rectangle: Length × Width = square feet. For a triangle: 0.5 × Base × Height. For a circle: π × radius². For irregular shapes, break them into rectangles and add the areas together.
There are 9 square feet in one square yard (3 ft × 3 ft). To convert square feet to square yards, divide by 9.
Divide the L-shape into two rectangles. Calculate the area of each rectangle separately, then add them together. This calculator does that automatically when you select the L-Shape option.
One acre equals 43,560 square feet. A square acre would be about 208.7 feet on each side.