The concept of a board foot can see confusing at first. We are so used to looking at materials in terms of their surface area and that’s why I think board feet confuses so many people. What you need to keep in mind with board feet is that it is a unit of volume just like a gallon or a liter.
The formula for computing board feet is:
(Length x Width x Thickness)/144
Note: Length, Width, and Thickness need to be in inches
The first part of the formula will give you the cubic inches of the board and dividing by 144 will convert cubic inches into board feet.
It’s really helpful to memorize the board foot amount of a few of the most common size boards you typically buy. This will help you to know or estimate board feet when purchasing materials.
Here are some common board sizes:
|4/4 8′ long||5/4 8′ long||8/4 8′ long|