Square footage calculator
Find the area of a room or space — rectangular, circular or triangular — in square feet or square meters.
Enter any consistent unit (feet or meters) — the result is shown per square unit you entered, plus the equivalent in the other system.
Fill in the fields and press Calculate to see your result here.
How this calculation works
Rectangle area is length × width. Circle area is π × radius². Triangle area is ½ × base × height. Since the unit you type in isn't specified, the result shows both a square-feet-style and square-meters-style conversion (1 square foot = 0.0929 square meters) so you can read off whichever matches what you entered.
Worked example
A room measuring 12 ft by 10 ft covers 120 sq ft. A circular rug with a 3 ft radius covers π × 3² ≈ 28.3 sq ft.
Tips
For an irregular room
Split it into rectangles (and a triangle or two if needed), calculate each separately, then add the areas together.
Use the same unit everywhere
Measure all sides in feet or all in metres. Mixing units is the most common cause of a wrong area.
Subtract cut-outs
For flooring or paint, take away areas such as a fireplace or built-in cupboard that you won't cover.
Allow for waste
Flooring and tile are usually ordered with about 5-10% extra to cover cuts and mistakes.
Frequently asked questions
Does this handle a full circle or just a sector?
This calculates the area of a complete circle. For a partial slice (a sector), multiply the full-circle result by the fraction of the circle it covers.
What if I have an oval or irregular shape?
Break it down into simpler shapes (rectangles, triangles, or a circle) that approximate it, and sum their areas.