Board Feet Calculator

Use a log rule like Doyle, Scribner, or International 1/4-inch. Measure the small-end diameter and length, then apply the rule's formula or lookup table. For rough estimates, the Doyle rule is common but tends to underestimate for small logs.

A board foot is 144 cubic inches of wood. Multiply thickness × width × length (all in inches), then divide by 144. A 1-inch thick, 12-inch wide, 12-inch long board equals exactly 1 board foot.

A 2x4x8 uses actual dimensions of 1.5 × 3.5 × 96 inches. That equals (1.5 × 3.5 × 96) / 144 = 3.5 board feet per 8-foot length.

A board foot measures volume (144 cubic inches), while a linear foot measures length only. Board feet account for thickness and width, making them the standard for rough lumber pricing. Linear feet are used for trim and moulding.

Red oak weighs approximately 3.6 to 4.2 pounds per board foot when kiln-dried (6-8% moisture content). Weight varies by species, moisture content, and whether the wood is green or dried.

4/4 (four-quarters) means the rough sawn thickness is approximately 1 inch. The quarter system measures rough thickness: 4/4 = 1 inch, 6/4 = 1.5 inches, 8/4 = 2 inches. After surfacing (S2S), the actual thickness is less.

Multiply the square footage by the thickness in inches, then divide by 12. Formula: Board Feet = (Square Feet × Thickness in Inches) / 12. This works because board feet measure volume.

Board feet measure actual wood volume, which is more accurate than linear feet for pricing rough lumber of varying widths and thicknesses. The system originated in the early US lumber industry to standardize trade across different dimensions.