Free calculator
Square Footage Calculator
Calculate square footage for rectangular, square or circular areas and convert the result to square yards and acres.
Your project details
Change the inputs below to match your project.
Planning tool only. Verify field measurements, material specifications and project requirements before ordering materials or starting work.
How to calculate square footage
For a rectangle, multiply length by width. For a square, multiply one side by itself. For a circle, use π × radius². The calculator also converts the result to square yards and acres.
For irregular spaces
Break the area into simple rectangles or other basic shapes, calculate each section separately, then add the results. This is usually more reliable than estimating one complex outline.
Related planning
Once you know area, use it in the Flooring Cost Calculator, Paint Calculator or Mulch Calculator.