Square Footage Calculator
Measure the area of rooms and irregular spaces in square feet or square metres.
About the Square Footage Calculator
Enter up to three rectangles, a triangle and a circle, in feet or metres. The calculator adds them up and gives the total in square feet, square metres, square yards and acres, and the cost if you enter a price per square unit.
Split an irregular room into rectangles, triangles and circles, work out each one and add them up.
The formula
Area = Σ (L × W) + ½ × b × h + π d² ÷ 4
- L × W
- each rectangle
- ½ × b × h
- a triangle's base times height, halved
- π d² ÷ 4
- a circle of diameter d
Worked example
An L-shaped room: 16 × 13 ft plus an 8 × 6 ft alcove
- 16 × 13 = 208 ft²; 8 × 6 = 48 ft²
- Total: 256 ft²
- = 23.78 m² = 28.44 yd²
Things to keep in mind
- Measure wall to wall at floor level; skirting and built-in units reduce the usable area slightly.
Questions people ask
How do I measure an L-shaped room?
Split it into two rectangles and add them.
How many square feet in a square metre?
10.7639 (1 ft² = 0.092903 m²).
Does a home's listed square footage include walls?
Usually yes for the whole home (gross area); room measurements don't, so they add up to less.