Lumber volume — board foot, cord and cubic foot
Lumber does not sell by volume in metres or gallons — it sells by product-specific historical units.
The lumber industry uses several volume units that survive from pre-industrial measurement. Each captures a different aspect of the wood product: dimensional lumber (board foot), fuel wood (cord), and finished panel sheets by area.
The exact definitions
1 board foot (bf, fbm) = 144 in³ = 2359.7 cm³ > 1 cord = 128 ft³ = 3.625 m³ (stacked, including air gaps) > 1 face cord = 1/3 of a full cord (varies regionally) > 1 MBF (thousand board feet) = 2.36 m³
Where each is used
Board foot: dimensional lumber pricing (2×4s, hardwood boards). Cord: firewood, pulp wood. Cubic foot / cubic metre: engineered lumber, plywood, industrial specification.
Worked example — deck project
A deck needs 320 linear feet of 2×6. Nominal 2×6 = 1.5 × 5.5 in actual. Board feet: 320 × (1.5 × 5.5)/12 = 220 bf. At $2/bf, materials = $440. Estimate in cubic feet (220 × 144/1728 = 18.3 ft³) and the price per ft³ triples the number — same wood, different unit.
Recap
bf ≠ ft³. Cord is stacked volume, includes air. Match units to product convention.
Try the converters mentioned in this article
FAQ
Is nominal size or actual size used?+
Board foot uses nominal size (2×6, 2×4). Actual dimensions are smaller after milling.
Is a 'thrown cord' the same as a full cord?+
Thrown (loose) cord is 180 ft³ = 1.4× stacked cord — accounting for random air gaps.
This article was written by The Turbo Unit Converter engineering desk (Applied metrology & engineering units) and last reviewed on 2026-07-07 against NIST SP 811 and the BIPM SI Brochure. Read our full editorial policy.