Measuring & Estimating

Board foot vs linear foot vs square foot — three 8-foot boards compared

Same 8-ft length, very different board feet. Linear feet ignore the cross-section and square feet ignore thickness — board feet is the volume, so order hardwood by the board foot.

Source: Board feet = T(in) × W(in) × L(ft) ÷ 12 (src/lib/calculators/boardFeet.js)
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What this diagram shows

Three boards, all 8 feet long, drawn at true relative scale to compare the three lumber units. A 1 by 4 by 8 feet is 8 linear feet, 2.67 face square feet, and 2.67 board feet. A 2 by 4 by 8 feet is 8 linear feet and the same 2.67 face square feet, but double the thickness makes it 5.33 board feet. A 1 by 12 by 8 feet is 8 linear feet but three times the width, so 8.0 square feet and 8.0 board feet. Linear feet ignore the cross-section, square feet ignore thickness, and board feet is the volume that captures both — which is why hardwood is ordered by the board foot, never by linear feet.

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