How to Calculate Square Footage
Part of Area & Volume
Quick answer
Multiply length (ft) by width (ft). A 12 ft × 10 ft room is 120 square feet. For odd shapes, split the space into rectangles, find each one's area, and add them together.
Square footage is just area measured in feet. The core formula is length × width, both in feet. If you measured in inches, divide by 12 first to convert to feet.
The formula
Square feet = Length (ft) × Width (ft)
Odd-shaped rooms
- L-shape: divide it into two rectangles, calculate each, and add them.
- Triangle: (base × height) ÷ 2.
- Circle: π × radius², where radius is half the diameter.
- Round every final figure up slightly to allow for waste when buying materials.
Common conversions
| From | To square feet |
|---|---|
| Square inches | ÷ 144 |
| Square yards | × 9 |
| Acres | × 43,560 |
| Square meters | × 10.764 |
FAQs
How do I calculate square footage from inches?
Convert each measurement to feet first by dividing by 12, then multiply length × width. Or multiply inches × inches and divide the result by 144.