Board Foot Calculator

A board foot is a unit of volume measurement for lumber. One board foot equals 1 inch thick × 12 inches wide × 12 inches long (144 cubic inches). The formula is: Board Feet = (Thickness in inches × Width in inches × Length in feet) / 12. Board footage measures the volume of lumber, not the surface area. This is important because thicker lumber contains more wood and costs more per board foot. Lumberyards use board feet for pricing commodity and hardwood lumber.

Board feet measure volume (thickness × width × length / 12), while linear feet measure only length regardless of width or thickness. A 2×4 that is 10 feet long = 6.67 board feet (2×4×10/12) but only 10 linear feet. Linear feet are used for dimensional lumber sold by length (studs, joists, rafters). Board feet are used for hardwood lumber and larger timbers. When comparing prices, always check whether the price is per board foot or per linear foot.

Conversions: Board Feet = (T × W × L) / 12 (T, W in inches, L in feet). Board Feet = (T × W × L) / 144 (all in inches). Cubic Feet = Board Feet / 12. Cubic Meters = Board Feet × 0.00236. One thousand board feet (MBF) = 83.33 cubic feet = 2.36 cubic meters. Standard lumber: 1000 BF of 2×4 ≈ 417 linear feet at 2×4 actual size. Hardwood is typically sold by the board foot while softwood (construction lumber) is sold by the linear foot.

Board foot calculations for pricing use nominal dimensions (the named size, like 2×4), not actual dimensions (1.5×3.5). This is the industry standard - you pay for the nominal volume even though the actual volume is less. For example, a 2×4 × 10 ft = 2×4×10/12 = 6.67 nominal board feet, but actual = 1.5×3.5×10/12 = 4.38 board feet. The difference accounts for milling waste. Always use nominal dimensions for pricing calculations.