How the area math works
Circle: π × (diameter ÷ 2)²
Triangle: base × height ÷ 2
Square yards are square feet ÷ 9. Acres are square feet ÷ 43,560. Square meters are square feet ÷ 10.764.
Worked example
An L-shaped room can be split into a 20 × 12 ft section (240 sq ft) and a 10 × 8 ft section (80 sq ft), for 320 sq ft total, or 35.6 square yards.
Measuring tips
Measure wall to wall at floor level and round up to the next inch. For odd shapes, split the space so the pieces don’t overlap. Triangles use the height measured at a right angle to the base, not the length of the sloped side.
Common questions
How do I find the square footage of an L-shaped room?
Split it into two rectangles that don’t overlap, calculate each, and add them. Enter each as its own area above.
How do I enter feet and inches?
Type it the way you’d say it: 12' 6", 12ft 6in, or 12.5. You can also type inches (150in) or meters (3.8m).
How many square feet are in an acre?
43,560 square feet.
How many square feet are in a square yard?
9 square feet. Carpet and sod are sometimes priced per square yard.
Related calculators
See how we calculate for every formula and constant used on this site.