Board Foot Calculator
Convert lumber dimensions into board feet for ordering and pricing.
Board feet needed
How board feet are calculated
A board foot is a volume measurement used throughout the North American lumber industry: one board foot equals a piece of wood 12 inches wide, 12 inches long, and 1 inch thick (144 cubic inches). Because rough lumber is priced by volume rather than by the piece, board feet let a mill, yard, or contractor compare and price boards of any dimension on the same scale.
The formula used above is: Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. Thickness and width are taken as nominal inches (the number stamped on the board, such as 2 for a 2x6), and length is measured in feet, which is why the result is divided by 12 rather than 144.
For a 2x6 that is 8 feet long, that's (2 × 6 × 8) ÷ 12 = 8 board feet. Multiply by the number of identical boards in the order to get a job-total, and multiply that by a price-per-board-foot quote to estimate material cost before it reaches the register.
Where these numbers come from
The formula and default values in this calculator are based on:
- Formula reflects the standard board-foot convention used by North American lumber yards and hardwood suppliers (nominal thickness × nominal width × length in feet, ÷ 12).
These are planning estimates. Check your local building code, product specifications, and a licensed contractor before you buy materials or build.
Frequently asked questions
Does board footage use nominal or actual lumber dimensions?
Board footage is traditionally priced using nominal dimensions (the size the board is called, like 2x6), not the smaller actual dressed size after milling. That's the industry convention this calculator follows, and it's how lumber yards and mills quote rough and dimensional lumber alike.
Why divide by 12 instead of 144?
Because length is entered in feet rather than inches. The full board-foot volume formula is (thickness in. × width in. × length in.) ÷ 144, but since 1 foot = 12 inches, substituting feet for the length term and dividing by 12 gives the identical result with one less unit conversion.
How is board footage different from linear footage?
Linear footage only measures length and ignores thickness and width entirely, so it works for trim or molding priced by the running foot. Board footage accounts for the full volume of the piece, which is why it's the standard for framing lumber, hardwood, and anything priced by the volume of wood delivered.
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