Square Footage Calculator

1. Select the shape. Choose from rectangle, circle, triangle, trapezoid, or ellipse. Most rooms are rectangles. Use triangle or trapezoid for angled rooms or plots. For circular pools, patios, or round rooms, select circle and choose whether to enter radius or diameter.
2. Enter dimensions in feet. All inputs use feet (not inches or yards). Convert inches to feet by dividing by 12, and yards to feet by multiplying by 3. For a room 144 inches long, enter 12. For a plot 5 yards wide, enter 15.
3. Read all four output units. The calculator shows square feet, square yards, square meters, and acres simultaneously. Square feet is the standard for US home improvement projects. Square yards is used for flooring and carpet. Square meters is used in most other countries and in scientific contexts. Acres is useful for large land areas.
4. Add multiple areas. For L-shaped rooms or irregular floor plans, split the space into rectangles (and other simple shapes), calculate each, and add the square footages together. The formula display under the results shows exactly what calculation was used.

Example: an L-shaped room can be split into a 20 × 12 rectangle (240 ft²) and a 10 × 8 rectangle (80 ft²) for a total of 320 ft². At 10.75 per square yard, flooring would cost 35.56 square yards × $10.75 = $382.

Square footage is the area of a two-dimensional space measured in square feet. One square foot is a square with sides 1 foot (12 inches) long. All area formulas produce a result in the same square units as the input dimensions used.

Common reference areas: a standard parking space is about 162 ft² (9 × 18 ft). A typical one-car garage is 200 to 240 ft². A standard US football field (end zones included) is 57,600 ft², or about 1.32 acres. An NBA basketball court is 4,700 ft². A tennis court is 2,808 ft². A suburban quarter-acre lot is 10,890 ft².