Linear Feet, Board Feet & Cubic Feet

The three measurements, and how they relate

Linear feet is simply length -- a 10-foot 2x4 is 10 linear feet, regardless of its thickness or width. Board feet is a volume measurement specific to the lumber trade: one board foot equals 144 cubic inches (a 12"×12"×1" piece). Cubic feet is the general-purpose volume unit (1,728 cubic inches).

Converting between them

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. Cubic feet = board feet ÷ 12 (since one board foot is 1/12 of a cubic foot). To go from linear feet to board feet, you need the board's thickness and width too -- linear feet alone doesn't carry volume information.

Worked example: a 2x6 (actual 1.5" × 5.5") that's 10 feet long: board feet = (1.5 × 5.5 × 10) ÷ 12 ≈ 6.88 board feet (note: board-foot pricing conventionally uses the nominal 2x6 width of 5.5", close to actual here -- see our nominal vs. actual guide for sizes where the gap is larger). That's about 0.573 cubic feet.

Standard board-foot and cubic-foot definitions used throughout the US lumber trade.