What is a board foot?
A board foot is a volume of lumber equal to a piece 1 inch thick, 12 inches wide and 1 foot long (144 cubic inches). The formula is thickness (in) × width (in) × length (ft) ÷ 12. Hardwood is usually priced per board foot, so this is how lumber yards quote it. Use nominal thickness (a "1-inch" board counts as 1″ even though it's actually thinner once surfaced).