Calculator
Square Footage Calculator
Convert room dimensions into square feet, square yards and material quantities.
Verified August 2026
Square footage
180 sq ft
- With waste allowance
- 198 sq ft
- Square yards
- 20
- Perimeter (per area)
- 54 ft
- Square meters
- 16.72
Estimates only. Local pricing, site conditions and code requirements change the real number.
The formula
Square feet = length x width; Square yards = square feet / 9
Carpet is sold by the square yard; nearly everything else is sold by the square foot.
Worked example
A 12 ft by 15 ft room is 180 square feet, or 20 square yards, with a 54 ft perimeter.
Frequently asked questions
How do I calculate square footage of an irregular room?
Break the space into rectangles, calculate each separately, and add them together. For triangles use one-half base times height.
Sources
Sources & verification
Last verified August 2026. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing — they are not quotes. Permit rules change; confirm with the building department before starting work.