A board foot is based on the thickness by width by length of the board

• A. Width By Thickness By Length
• B. Length By Width By Thickness
• C. Thickness By Width By Length
• D. Thickness By Length By Width

Answer: (C)

Board feet measure volume using the cross-section first and then the length, based on the standard block of wood that is 1 inch thick by 12 inches wide by 12 inches long. Because of that definition, the calculation uses thickness and width in inches and length in feet. The formula multiplies thickness (in inches) by width (in inches) by length (in feet) and then divides by 12, since 1 board foot equals 1" × 12" × 12". For example, a board that is 3/4" thick, 9" wide, and 8' long has: (0.75 × 9 × 8) / 12 = 4.5 board feet. Using this order aligns with the standard definition and keeps units consistent; changing the order would mix units and wouldn’t reflect the board-foot measure properly.