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Lumber Calculator

Calculate board feet and total cost for your lumber needs. Add multiple line items for a full materials list.

Lumber Dimensions

Board Feet (per piece)

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Total Board Feet

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Total Cost

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Common Lumber Sizes

NominalActualBF per 8ftCommon Use
2x41.5" x 3.5"5.33Framing, studs
2x61.5" x 5.5"8.0Floor joists, decking
2x81.5" x 7.25"10.67Headers, rafters
2x101.5" x 9.25"13.33Floor joists, beams
2x121.5" x 11.25"16.0Ridge boards, stairs
4x43.5" x 3.5"10.67Posts, columns

Board Feet Formula

Board Feet = (Thickness in inches x Width in inches x Length in feet) / 12

One board foot = a piece of lumber 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches).