Formula

Board Feet = (Thickness × Width × Length in inches) ÷ 144

One board foot equals a piece of lumber 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). Lumber is priced per board foot at most hardwood suppliers.

Examples

1 × 6 × 8 ft board

(1 × 6 × 96) ÷ 144 = 4.0 board feet

Result: 4.00 BF

2 × 4 × 10 ft board

(2 × 4 × 120) ÷ 144 = 6.67 board feet

Result: 6.67 BF

FAQ

Use nominal dimensions when buying and pricing lumber. A "2×4" is nominally 2 inches × 4 inches even though its actual size is 1.5 × 3.5 inches. Hardwood dealers use nominal dimensions for board foot pricing.

Board feet are the standard unit for pricing hardwood lumber. Softwood (pine, spruce) is typically sold by the linear foot, while hardwood (oak, walnut, maple) is sold by the board foot.