Board Foot Calculator
Calculate board feet for rough lumber using thickness, width, length, and quantity.
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How this calculator works
Board feet = thickness(in) × width(in) × length(in) ÷ 144 × quantity.
Worked example
Ten 1 × 8 × 96 in boards equal about 53.33 board feet.
Use actual lumber dimensions when accuracy matters
A board foot is a volume equal to 144 cubic inches. Hardwood is often priced by nominal thickness and measured width and length, while surfaced stock may be smaller than its named size. Ask the seller whether tally measurements are rough, surfaced, or net before comparing the calculator with an invoice.
Measure boards consistently and group pieces that share the same thickness and width. For mixed stock, calculate each group and add the totals.
Allow for milling and selection
Purchase quantity should include defects, end checks, grain matching, test cuts, and the material removed during jointing and planing. The appropriate allowance depends on grade and project layout; a clear, straight-grained furniture part may require more selection than a short utility component.
Sources & assumptions
The formula follows the conventional 144-cubic-inch board foot definition described in NIST Handbook 130. Lumber may be sold using nominal rather than dressed dimensions.
Frequently asked questions
Why divide by 144?
One board foot is a volume of 144 cubic inches, traditionally 1 in × 12 in × 12 in.
Should I use nominal or actual dimensions?
Use the dimensions your lumber dealer prices by. Rough lumber is commonly sold using nominal thickness conventions.