Square Footage Calculator
Add up one or more rectangles, circles, triangles or custom areas and subtract excluded spaces.
Behind the numbers
How area is calculated
Rectangle = length × width
Circle = π × radius²
Triangle = base × height ÷ 2
Circle = π × radius²
Triangle = base × height ÷ 2
Real-world project example
How many square feet in a 12 × 16 ft patio?
Multiply 12 ft by 16 ft to get 192 sq ft. A second 6 × 8 ft section adds 48 sq ft, for 240 sq ft total. Use separate shapes or sections when a room, patio or lawn is not one rectangle.
Before you buy materials
Subtract holes and excluded areas where relevant. Square feet measure surface area, not volume: to order gravel, concrete or mulch, you will also need depth.
Adjust the measurements, waste allowance and purchase options in the calculator above to estimate your own project; examples are for planning only.
Project guide: Sod rolls and pallets for a 1,000 sq ft lawn →