Square Footage Calculator
Calculate square feet, square meters, square yards, acres, and perimeter for one or more rectangular spaces.
For a rectangle, square footage is length × width. Calculate irregular rooms as separate rectangles, add their areas, and subtract only openings that will not receive material.
13.33 yd² · 11.15 m² · 0.0028 acres · 44 linear ft perimeter.
Split L-shaped or irregular rooms into rectangles and add them as separate calculations.
Step by step
- 1
Measure each rectangular section at its longest usable length and width.
- 2
Add extra sections for alcoves or adjoining spaces and review the combined perimeter when trim is needed.
- 3
Use the finished area as the base for a material-specific waste allowance rather than adding waste twice.
Check the estimate before you buy
Calculate square feet, square meters, square yards, acres, and perimeter for one or more rectangular rooms or outdoor areas after exclusions.
A 12 × 10 ft room is 120 sq ft and 44 linear ft around the perimeter. Two matching rooms total 240 sq ft before exclusions, equal to 26.67 square yards or about 22.30 square meters.
How the calculation works
Each rectangle uses length × width. Matching spaces are multiplied, exclusions are subtracted, and the result converts to square meters, square yards, and acres.
Square Footage Calculator FAQ
How do I measure an L-shaped room?
Divide it into non-overlapping rectangles, calculate each area, and add the results.
Are square feet and linear feet interchangeable?
No. Square feet measure surface area; linear feet measure distance such as perimeter or trim.
How many square feet are in a square yard?
One square yard equals 9 square feet.
How do I convert square feet to square meters?
Multiply square feet by 0.092903. The calculator displays both.
Reference: NIST U.S. customary and SI unit definitions. Results are practical estimates; complete labels, package directions, product specifications, and qualified professional advice take priority.