Board Foot Calculator for Lumber
Board feet are how hardwood is priced and ordered. One board foot is a piece 1 inch thick, 12 inches wide and 12 inches long — 144 cubic inches. This calculator accepts fractional lumber sizes, adds a waste factor, and returns the number you actually need to buy.
Accepts fractions: 4/4, 8/4, 5/4
Results
Enter your measurements above and press Calculate.
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Questions people ask
How do I calculate board feet?
Board feet = (thickness in × width in × length in × quantity) ÷ 144. Length must be in inches, so an 8 foot board is 96 inches. A 1 × 8 board 8 feet long is 5.33 board feet.
What does 4/4 lumber mean?
4/4 is rough-sawn lumber one inch thick, expressed in quarter-inch fractions. It is milled down to 13/16 inch or thinner for most projects, but it is still sold and billed as 4/4.
How much waste should I allow?
Plan 10% for simple trim, 15% for joinery or a project with many cuts, and 20% for figured stock or boards you will rip. Kiln-dried stock bought by the board can absorb more, because you may need to cut around defects.
Is a board foot the same as a solid foot?
No. A board foot is a volume, not a length. A 1 inch thick × 12 inch wide × 12 inch long piece is 1 board foot regardless of the species or the actual piece of wood you end up cutting.
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