Square Footage Calculator
Find the square footage of any room, floor plan or lot. Add rectangles, circles and triangles in feet, inches, yards or meters. Results update as you type.
Calculate area
How to calculate square footage
Rectangle: length × width. Circle: π × (diameter ÷ 2)². Triangle: ½ × base × height. For L-shaped or irregular rooms, split the space into simple shapes and add them. Example: a 12 ft × 10 ft room is 120 sq ft. Convert inches to feet (÷ 12) before you multiply.
Square feet to acres converter
Acres = sq ft ÷ 43,560. Acres to sq ft: multiply by 43,560.
| Square feet | Acres |
|---|
Project calculators
Use your total above (it fills in automatically) or type any area.
Flooring cost
Tile count
Mulch
Concrete slab
Paint coverage
FAQ
How do I calculate square footage?
Multiply length by width in feet. A 12 × 10 ft room is 120 sq ft. For odd shapes, split into rectangles, triangles and circles and add them.
How many square feet are in an acre?
43,560. A quarter acre is 10,890 sq ft and a half acre is 21,780 sq ft.
How much extra flooring should I buy?
Add 10% for straight layouts and 15–20% for diagonal or patterned layouts.
How do I convert square meters to square feet?
Multiply by 10.764.