Board Foot Calculator Guide
Understanding Board Feet
A "Board Foot" (FBM) is a unit of volume used in the lumber industry. Unlike linear feet (which just measures length) or square feet (area), a board foot measures the actual amount of wood in a piece of lumber.
The Definition
One board foot is equal to a piece of wood that is:
12 inches wide × 12 inches long × 1 inch thick (144 cubic inches).
Formula: (Thickness" × Width" × Length') / 12
Note: Thickness and Width are in inches, Length is in feet.
Why Use Board Feet?
Rough Lumber Pricing
Hardwoods (Oak, Walnut, Cherry) are sold by the board foot because they come in random widths and lengths.
- Fairness: You pay for the actual volume of wood you get.
- Comparison: Easy to compare prices between different species.
Dimensional Lumber
Softwoods (Pine, Fir) at big box stores are sold by the "piece" (linear foot), not board foot.
- 2x4x8: Sold as "one stud".
- Calculation: A 2x4x8 is actually 5.33 board feet.