Hardwood lumber is sold by the board foot — a volume of 1 ft × 1 ft × 1 in (144 cubic inches). Enter the size and number of boards to find the total board feet and cost.
Hardwood is measured by its rough thickness in quarters (4/4 = 1 inch, 8/4 = 2 inches). For dimensional softwood, suppliers usually calculate board feet from the nominal size (a 2×6 counts as 2 × 6 inches).
Formula
Board feet = Thickness (in) × Width (in) × Length (ft) ÷ 12
Equivalently, thickness × width × length in inches ÷ 144.
Worked example
One 2 × 6 board, 8 ft long, is 2 × 6 × 8 ÷ 12 = 8 board feet. Ten of them make 80 board feet.
Frequently asked questions
What is a board foot?
A unit of lumber volume equal to a board 12 inches long, 12 inches wide and 1 inch thick: 144 cubic inches.
How many board feet are in a 2×4×8?
Using nominal sizes, 2 × 4 × 8 ÷ 12 = 5.33 board feet.
Last updated · Calculations checked by automated tests· Editorial policy