Which unit is commonly used to measure lumber volume?

• A. Square feet
• B. Board feet
• C. Cubic feet
• D. Linear feet

Answer: (B)

Lumber volume is expressed in board feet because this unit accounts for thickness, width, and length in a single measure, giving a true sense of how much wood you have in a piece. A board foot represents a board 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). The common calculation used in carpentry is board feet = thickness in inches × width in inches × length in feet ÷ 12. For example, a piece that is actually 1.5 inches thick, 3.5 inches wide, and 8 feet long equals 1.5 × 3.5 × 8 ÷ 12 = 3.5 board feet.

Square feet covers area, not volume, so it doesn’t reflect how much wood is there in thickness and width. Cubic feet gives volume but isn’t as convenient for standard lumber sizes and pricing. Linear feet measures only length. Board feet, by combining the three dimensions, is the practical, industry-standard unit for estimating and pricing lumber.