How to calculate square footage
For a rectangle or square, multiply length by width in feet. A room 12 ft long and 10 ft wide is 120 sq ft.
rectangle = length × width
triangle = base × height ÷ 2
circle = π × (diameter ÷ 2)²
half circle = π × (diameter ÷ 2)² ÷ 2
Irregular and L-shaped rooms
Split the floor plan into simple shapes that don't overlap. An L-shaped room becomes two rectangles; a bay window is a rectangle plus two small triangles. Add each shape as its own area above and the calculator totals them.
Lengths can be typed in feet and inches, like 12' 6" or 12 6, or in meters like 3.8m.
Square footage conversions
| Unit | Equals |
|---|---|
| 1 square yard | 9 sq ft |
| 1 square meter | 10.764 sq ft |
| 1 acre | 43,560 sq ft |
| 1 square (roofing) | 100 sq ft |
What to use square footage for
Once you have the area, the other calculators turn it into materials: flooring boxes, gallons of paint, mulch, gravel or a concrete slab.
Frequently asked questions
How do I calculate the square footage of a room?
Measure the length and width in feet and multiply them. A 12 × 14 ft room is 168 sq ft. For irregular rooms, split them into rectangles and add the areas.
How many square feet is a 12x12 room?
144 square feet.
How do I convert square feet to square yards?
Divide by 9. For example, 270 sq ft is 30 sq yd. Carpet is often priced per square yard.