Board Foot
A unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches).
A board foot (bf) is the standard unit for measuring and pricing lumber volume, especially for hardwoods and premium species. One board foot equals 144 cubic inches: a board 1 inch thick, 12 inches wide, and 12 inches long. The formula is: (Thickness in inches × Width in inches × Length in feet) ÷ 12.
Hardwood lumber (oak, maple, walnut) is sold by the board foot because it is milled in random widths and lengths. Softwood construction lumber (2x4s, 2x6s) is sold by the linear foot or by count. Understanding board feet helps homeowners price custom millwork, hardwood flooring, cabinetry, and furniture-grade lumber accurately.
Prices per board foot vary enormously by species: common pine may be $2–$4/bf, while figured walnut can reach $20–$40/bf. When comparing millwork quotes, confirm whether prices are by board foot or by linear foot, as confusing the two can lead to significant estimation errors.
Real-World Example
The custom cabinet shop quoted 320 board feet of quarter-sawn white oak at $8.50/bf for the library built-ins, totaling $2,720 in lumber alone.