Board Foot Calculator (Lumber)

Board Foot Calculator

Calculate board feet for hardwood and lumber pricing — enter thickness, width, length and quantity.

A board foot equals 144 cubic inches (1 in × 12 in × 12 in). Rough lumber is sold by nominal thickness in quarters (4/4 = 1 in). Estimate only — planed (S4S) boards measure less than nominal.
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How to calculate board feet

Board feet = (thickness in × width in × length ft) ÷ 12. One 1×6 board, 8 ft long is (1 × 6 × 8) ÷ 12 = 4 board feet. Hardwood is priced per board foot, so this is how you compare costs across sizes. Remember 4/4 means 1-inch nominal thickness.