How Lumber Is Measured
Understand linear, area and volume measurements used for lumber.
Length, area and volume answer different questions
Linear feet records run length. Square feet records face area. Board feet, cubic feet and cubic metres record volume. Piece count records units but not size. A useful measurement statement names both the number and the quantity type, such as 48 linear feet of moulding or 32 BF of rough walnut.
Confusion arises when price units are compared without the missing dimensions. A price per linear foot cannot be converted to price per BF unless thickness and width are known. Square-foot coverage cannot become BF without thickness.
Dimensions depend on manufacturing stage
Rough, surfaced and finished boards may carry the same product history but have different physical dimensions. Nominal labels may describe a trade category rather than the measured piece. Record whether dimensions were measured, quoted nominally, rounded under a tally rule or taken after machining.
Hardwood and softwood contexts
Hardwood is commonly tallied by board-foot volume with trade practices governing thickness and rounding. Construction softwood is often identified by nominal sizes with standard dressed dimensions. These are contexts, not automatic calculator transformations; the seller’s written basis should remain with the result.
Logs require a named scale
A log-rule BF figure estimates potential sawn yield from diameter and length. It cannot be compared directly with a sawn-board BF inventory unless the difference between estimated input and recovered output is understood. Always name Doyle, Scribner variant or International ¼-inch.
Questions about this topic
What does linear footage omit?
It omits thickness and width.
Are nominal dimensions wrong?
No. They are useful trade labels, but they are not necessarily physical measurements.
Is log BF measured the same way as board BF?
No. Log rules model yield; board feet of sawn stock is geometric volume.
Related BoardFoot Bench pages
Method and content reviewed 3 September 2026.