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SESK: Stuff Everyone Should Know · sesk.info/wood-board-foot-definition

How big is one board foot of lumber?

A board 12 inches long, 12 inches wide, and 1 inch thick.

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  1. 12 in. long by 12 in. wide by 2 in. thick
  2. 12 in. long by 6 in. wide by 1 in. thick
  3. 12 in. long by 12 in. wide by 1 in. thick ✔

Why: A board foot is 144 cubic inches of wood, one foot square and one inch thick.

Huh, didn't know that: Lumber with a nominal thickness of less than 1 inch is still calculated as 1 inch.

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What is a tree's least favorite month? Sep-timber!
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References

Answer: 12 in. long by 12 in. wide by 1 in. thick. A board foot is 144 cubic inches of wood, one foot square and one inch thick.

  1. Wood Handbook: Wood as an Engineering Material, FPL-GTR-282 (USDA Forest Products Laboratory, 2021) research.fs.usda.gov/treesearch/62200
    A unit of measurement of lumber represented by a board 12 in. long, 12 in. wide, and 1 in. thick or its cubic equivalent.
    Checked 2026-10-10.

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