Board Feet to Square Feet: How to Convert
Part of Interior & Finishes
Quick answer
Square feet = board feet ÷ thickness in inches. For 1-inch (4/4) lumber, board feet and square feet are equal. For 2-inch (8/4) stock, one board foot only covers half a square foot.
These two units measure different things, which is why there's no single conversion number. A board foot is a volume (144 in³); a square foot is surface area. To get from one to the other you have to know how thick the wood is.
The conversion
- Square feet covered = board feet ÷ thickness (in)
- Board feet = square feet × thickness (in)
- For 4/4 (1 inch) lumber the two numbers are the same.
Coverage by thickness
| Thickness | 1 board foot covers |
|---|---|
| 1/2 in | 2.0 ft² |
| 3/4 in | 1.33 ft² |
| 1 in (4/4) | 1.0 ft² |
| 1.5 in (6/4) | 0.67 ft² |
| 2 in (8/4) | 0.50 ft² |
Example: 240 board feet of 4/4 stock covers about 240 ft² of surface; the same 240 board feet of 8/4 stock covers only ~120 ft² because it's twice as thick.
FAQs
What's the difference between a board foot and a square foot?
A board foot is volume (it includes thickness); a square foot is flat area. Lumber is sold by the board foot, while flooring and sheet goods are sold by the square foot.