A Lineal Foot is the measurement of the length of the board, regardless of the width or thickness of the board.
A Board Foot is a volume measurement of the board. It takes into account the width and thickness as well as the length of the board.
A simple way to calculate the number of board feet in a board is to use this formula.
- Times the width by the thickness in inches (ie a 2″x6″ would be 12″)
- Divide that number by 12.
That will give you how many board feet will be in each lineal foot. In the case of a 2×6, one board feet equals one lineal foot.
If you are looking at a 1″x6″, you get 1″x6″=6. When you divide that by 12 you get 1/2. That tells you that each lineal foot in a 1″x6″ board is a half of a board foot.
So an 8′ 2″x6″ will be 8 board feet but an 8′ 1″x6″ will be 4 board feet.