How it works
For a rectangular room or floor, multiply the length by the width. The result is an estimate of usable area and does not subtract walls, columns, doors, or irregular sections.
Standard formula
length × widthWorked example
A 20 ft by 15 ft room has 300 square feet of area.
Frequently Asked Questions
How do I calculate an L-shaped room?
Split it into rectangles, calculate each area, then add them together.
Does this include waste for flooring?
No. Add a separate waste allowance, often 5% to 15% depending on the material and layout.
Can I enter inches?
Convert inches to feet first, or use the Unit Converter.
Is square footage the same as perimeter?
No. Square footage measures area; perimeter measures the distance around the boundary.