Enter your board's Length, Width, and Thickness — plus the Number of Boards — and the Board Foot Calculator works out the Board Feet per Board, your Total Board Feet across the whole batch, and the equivalent Volume in Cubic Feet.
Board Feet per Board
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Total Board Feet
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Volume in Cubic Feet
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A board foot is a unit of volume used to measure lumber. By definition, one board foot equals a piece of wood that is one inch thick, one foot wide, and one foot long, or 144 cubic inches total.
To calculate board feet, use the formula: board feet = length (ft) × width (in) × thickness (in) ÷ 12. The length must be in feet while width and thickness are in inches.
The board feet in a 2x4 depends on its length. An 8-foot 2x4 contains approximately 5.33 board feet (8 × 3.5 × 1.5 ÷ 12). Note that a 2x4's actual dimensions are 1.5" × 3.5".
A linear foot measures only length, while a board foot measures volume (length × width × thickness). Linear feet are used for pricing materials like trim, while board feet are used for lumber pricing.
Measure the length in feet, then the width and thickness in inches. Multiply length × width × thickness, then divide by 12. Always use actual dimensions, not nominal lumber sizes.
For logs, use the Doyle formula: Board Feet = ((diameter - 4) ÷ 4)² × length, where diameter is measured at the small end in inches and length is in feet. This accounts for waste and bark removal.
Board feet became the industry standard because it provides a convenient way to price lumber of varying dimensions. One board foot equals 1/12 of a cubic foot, making calculations easier for the lumber trade.