Formulas
- Rectangle: length × width
- Triangle: ½ × base × height
- Circle: π × (diameter ÷ 2)²
- L-shape: split into two rectangles and add them
1 sq yd = 9 sq ft. 1 sq ft = 0.09290304 m² (exact).
Tips for measuring a room
- Measure wall to wall at floor level, in two places, and use the larger number.
- Closets count if the flooring goes into them.
- For flooring, add 5–10% for cuts — or use the tile calculator.
Frequently asked questions
How do I find the square footage of an odd-shaped room?
Break it into rectangles and triangles, calculate each one, then add them — use “Add another area”.
How many square feet is a 12×12 room?
144 sq ft.
Sources
Last reviewed 2026-10-14. Estimates only — get written quotes from licensed local contractors before you decide.