📐 Square Footage Calculator
Find the area of a room, yard or plot in square feet, square meters and acres – and what it costs at a price per square foot.
Quick answer: Square footage = length × width. A 12 × 15 ft room is 180 sq ft, which is 16.72 m² or 20 square yards.
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Square Footage Calculator inputs
Result
Area
180 sq ft
12 × 15 = 180 sq ft
| Square feet | 180 |
| Square meters | 16.723 |
| Square yards | 20 |
| Acres | 0.00413 |
How to calculate square footage
Area measures the flat surface inside a shape. For the most common shapes the formulas are simple – just make sure all lengths use the same unit before you multiply.
Rectangle = L × W · Triangle = base × height ÷ 2 · Circle = π × r²
Worked example
A living room 12 ft wide and 15 ft long: 12 × 15 = 180 sq ft. Multiply by 0.0929 to get 16.72 m², or divide by 9 for 20 square yards. At $4 per sq ft for new carpet that is $720.
Area formulas and examples
| Shape | Formula | Example |
|---|---|---|
| Rectangle | length × width | 12 × 15 = 180 sq ft |
| L-shape | (L₁ × W₁) + (L₂ × W₂) | 12 × 15 + 6 × 8 = 228 sq ft |
| Circle | π × (diameter ÷ 2)² | 10 ft diameter = 78.54 sq ft |
| Triangle | base × height ÷ 2 | 10 × 8 ÷ 2 = 40 sq ft |
Unit conversions
- 1 sq ft = 0.0929 m² = 144 sq in
- 1 m² = 10.764 sq ft
- 1 square yard = 9 sq ft
- 1 acre = 43,560 sq ft = 4,046.86 m²
Measuring tips
- Measure wall to wall at floor level and round up to the nearest inch or centimeter.
- Break complex rooms into rectangles and triangles, then add them up.
- For real-estate listings, follow local rules on whether to include garages, stairs and unheated space.
- When buying materials, add 5–15% for waste – see the flooring calculator.
Frequently asked questions
How do I calculate square feet?
Measure the length and width in feet and multiply them. A room 10 ft by 14 ft is 140 sq ft. If you measured in inches, divide the result by 144.
How do I find the square footage of an L-shaped room?
Split the L into two rectangles that do not overlap, work out each area and add them together. Choose the L-shape option and enter both rectangles.
How many square feet are in an acre?
One acre is exactly 43,560 square feet, or about 4,047 square meters. A typical American football field without end zones is about 1.1 acres.
How do I convert square meters to square feet?
Multiply square meters by 10.764. For example, 20 m² × 10.764 ≈ 215.3 sq ft. To go the other way, divide square feet by 10.764.