What it works out
Enter the thickness, width and length of one piece and how many pieces you need. You get the board feet per piece, the total, and an order quantity with waste added. Use the actual measured size of the board, not the nominal name, because a board labelled 2 by 6 is smaller than that. Waste is added first and the total is rounded up once.
You enter
- Thickness
- Width
- Length
- Number of pieces
The formula
- Per piece
- thickness × width × length ÷ 144, with all three in inches
- Total
- per piece × count
In words: Per piece = thickness times width times length divided by 144, with all three in inches; total = per piece times count
Worked example
One piece, 2 in thick, 4 in wide and 8 ft long
- Thickness 2 in
- Width 4 in
- Length 8 ft = 96 in
- Pieces 1
- Board feet = 2 × 4 × 96 ÷ 144 = 5.33
For ten pieces, multiply by ten: waste is then added and the total rounded up once.
Good to know
- Use actual measured sizes, not nominal names: a board sold as 2 by 6 is smaller than that.
- One board foot is 144 cubic inches.
- A calculator, not a building-code check: confirm local rules with your building authority.
Questions
What is a board foot?
A volume of lumber equal to a board 1 ft long, 1 ft wide and 1 in thick: 144 cubic inches.
Nominal or actual size?
Actual. A nominal 2 by 4 measures about 1.5 in by 3.5 in.