Board Foot Calculator

A board foot is a unit of volume used to measure lumber. It equals the volume of a board 12 inches long, 12 inches wide, and 1 inch thick (144 cubic inches). Board feet are the standard unit for pricing hardwoods and specialty lumber in North America.

For a 2×4 that is 8 feet long: (2 × 4 × 8) ÷ 12 = 5.33 board feet. Remember, a "2×4" uses nominal dimensions. The actual dimensions after surfacing are 1.5 × 3.5 inches, but lumber is typically sold using nominal sizes.

Use nominal dimensions when purchasing lumber, as that's how it's priced and sold. A "2×4" is priced as 2×4 even though it actually measures 1.5×3.5 inches. For project planning where fit matters, use actual dimensions.

Prices vary widely by species. Softwoods like pine: $2-5/bd ft. Common hardwoods like oak or maple: $4-10/bd ft. Premium hardwoods like walnut or cherry: $8-15/bd ft. Exotic species can exceed $20/bd ft. Prices also depend on grade and thickness.

There are exactly 12 board feet in one cubic foot. Conversely, one board foot equals 1/12 (0.0833) cubic foot or 144 cubic inches.

Board footage accounts for thickness and width, giving a true measure of wood volume. A 1×6 and 2×12 of the same length contain very different amounts of wood. Board feet pricing ensures you pay proportionally for the actual material received.

Quarter notation indicates thickness in quarters of an inch. 4/4 = 1 inch, 5/4 = 1.25 inches, 6/4 = 1.5 inches, 8/4 = 2 inches. Use these values for thickness in the formula: (Thickness × Width × Length) ÷ 12.

For basic cuts: 10%. For furniture with joinery: 15-20%. For projects requiring grain matching or defect-free pieces: 20-25%. Rough lumber that needs planing: add another 10-15% for thickness loss.