How Board Feet Work

The Formula

Board Feet = (Thickness × Width × Length) ÷ 144. Where thickness and width are in inches and length is in inches (convert feet by multiplying by 12). One board foot is 144 cubic inches of wood.

Nominal vs Actual Dimensions

A 2×4 actually measures 1.5" × 3.5". A 1×6 is actually 0.75" × 5.5". Board feet are calculated using nominal dimensions at the sawmill. When ordering, use nominal sizes but expect actual delivered dimensions to be smaller.

Waste Allowance

Always add 10–15% for waste from cutting, defects, and end splits. For complex cuts or decorative projects, add 20%. Buying too little means a second delivery and the possibility of a different batch with slightly different colour.

Lumber Board Feet Calculator

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