Square Footage Calculator

Calculate the area of a room, lawn or lot in square feet. Supports rectangles, circles, triangles and trapezoids; split L-shaped rooms into rectangles and add them up.

Square feet

120 ft²

  • Square yards13.33 yd²
  • Square meters11.15 m²
  • Acres0.0028

Estimates only. Round up when you order, and confirm structural details with your local building code.

How to use it

  1. Pick the shape.
  2. Enter the dimensions.
  3. For repeated identical areas, set the quantity.

The formula

Rectangle = length × width

Triangle = base × height ÷ 2

Circle = π × (diameter ÷ 2)²

Trapezoid = (top + bottom) ÷ 2 × height

Worked example

ShapeRectangle / square
Length (or base)12 ft
Width (or height)10 ft
Number of identical areas1

Result

Square feet120 ft²
Square yards13.33 yd²
Square meters11.15 m²
Acres0.0028

Tips before you order

  • Measure to the nearest inch and convert: 10 ft 6 in = 10.5 ft.
  • For flooring, measure each room separately and add waste per room.

Questions

How do I calculate square footage of an L-shaped room?

Split it into two rectangles, calculate each one, and add them together.