How we worked it out
Updated as you change the numbers.
- Area = length × width = 12 ft × 10 ft = 120 sq ft.
- Square yards = sq ft ÷ 9; square meters = sq ft × 0.0929; acres = sq ft ÷ 43,560.
Method and assumptions
Every length is converted to feet first (1 in = 1/12 ft, 1 yd = 3 ft, 1 m = 3.2808 ft), so you can mix units. Rectangles are length × width, circles π × radius², and triangles base × height ÷ 2.
For an L-shaped room, split it into two rectangles that don’t overlap and enter each one. For more complicated shapes, split them into rectangles and triangles and add the areas.
Tips
- Measure wall to wall at floor level, and round up to the next inch.
- For flooring, add 5 to 15% for waste; the flooring calculator does this for you.
Questions
How do I calculate square feet?
Multiply the length by the width, both in feet. A room 12 ft by 10 ft is 120 sq ft. If you measured in inches, multiply and divide by 144.
How many square feet are in an acre?
43,560 sq ft, which is about 4,047 square meters.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.