What a board foot is
A board foot is a volume of wood 12" × 12" × 1" thick (144 cubic inches). Hardwood is priced by the board foot; construction lumber is usually sold by the piece, but board feet help compare prices.
Example: a 2 × 6 that's 8 ft long is 2 × 6 × 8 ÷ 12 = 8 board feet. Ten of them are 80 BF, which at $6 a board foot costs $480. A 4/4 (1") hardwood board 6" wide and 8 ft long is 4 BF.
Nominal vs actual size
Board feet use nominal dimensions: a 2 × 6 is sold as 2" × 6" even though it measures 1½" × 5½" after drying and planing. Rough hardwood is sold by quarters: 4/4 is 1", 5/4 is 1¼", 8/4 is 2". Buy 15% to 30% extra hardwood for defects and milling waste.
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Frequently asked questions
How many board feet in a 2x4x8?
5.33 board feet: 2 × 4 × 8 ÷ 12.
How do I calculate board feet for hardwood?
Multiply thickness in inches by width in inches by length in feet, and divide by 12. Use the nominal thickness: 4/4 is 1", 8/4 is 2".
What is the price per board foot?
It varies widely: common softwoods often cost $2 to $5, and hardwoods like oak and maple $5 to $12, with exotic species far more.
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