Square Footage Calculator
Use this square footage calculator to find the area of a room, floor, lawn, or lot. For a rectangle, area = length × width; a triangle is ½ × base × height; a circle is π × r²; a trapezoid is ½ × (base A + base B) × height. Pick a unit and a shape, or add several sections and subtract cut-outs. See square feet, square yards, square inches, and square meters, plus optional waste and cost. Keep both sides in the same unit, and add a waste percent before you order flooring, paint, or tile.
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Square feet (sq ft)
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Square yards (sq yd)
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Square inches (sq in)
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Square meters (sq m)
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Square feet with waste (sq ft)
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Total cost (with waste)
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1 m = 3.280839895 ft. Rectangle: L × W. Triangle: ½ × base × height. Circle: π × r². Trapezoid: ½ × (A + B) × height. Cost uses the area with waste.
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- Cubic Yard Calculator Length × width × depth to cu yd, cu ft, m³ and tons.
- Flooring Calculator Boxes, planks, underlayment and cost.
- Carpet Calculator Square yards, roll length, seams and cost.
- Paint Calculator Gallons, quarts and cost of paint for a room.
- Tile Calculator Tiles, boxes and cost for a room or wall.
- Drywall Calculator Drywall sheets, joint compound, tape and screws for a room.
How it works
- How do I calculate the square footage of a room?
- Measure the length and width in feet and multiply them. A 12 ft × 10 ft room is 12 × 10 = 120 sq ft. If you measured in inches, divide the product by 144; in yards, multiply by 9. Keep both sides in the same unit—mixing feet and inches is a common mistake that skews the area.
- How do I measure an L-shaped or irregular room?
- Split the floor plan into rectangles, find each area, and add them. Or measure the outer rectangle and subtract the missing corner: 20 × 15 = 300 sq ft minus an 8 × 6 cut-out (48 sq ft) leaves 252 sq ft. In the multiple sections mode, tick Subtract for cut-outs. Sketch first so you do not count an overlapping strip twice.
- How do I convert square meters to square feet?
- Multiply square meters by 10.7639 (1 m = 3.280839895 ft, squared). A 3 m × 4 m room is 12 sq m, which is 129.17 sq ft. To go back, divide square feet by 10.7639. Convert the finished area, or convert each length to feet first—do not apply 10.7639 to a linear meter by itself.
- How much extra flooring should I buy for waste?
- A common rule of thumb is 5–10% extra for straight layouts and 10–15% for diagonal or patterned layouts; follow your flooring manufacturer's advice. For 120 sq ft, 10% waste means ordering 132 sq ft, then rounding up to whole boxes. Skip waste only if the supplier already cut and numbered the pieces for your plan.
- What is the difference between square feet and linear feet?
- Linear feet measure length along a line, such as trim or a single board. Square feet measure area (length × width). An 8-foot board that is 6 inches wide covers 8 × 0.5 = 4 sq ft. Buying by the linear foot when you need coverage by the square foot under-orders material.