BF, MBF, FBM and Lumber Measurement Abbreviations
A cautious glossary of common lumber measurement shorthand.
Write the unit before trusting the abbreviation
BF and FBM commonly refer to board feet. MBF is used here for 1,000 board feet. Linear foot may appear as LF, and square foot as ft² or SF. Cubic units include ft³ and m³. Abbreviations are compact but can be regional, organisational or context-dependent.
A purchase order should define an abbreviation at first use, especially M, MBF and MMBF. Do not infer that a prefix follows financial or metric convention when the lumber document states otherwise.
Dimension and surfacing shorthand
Quarter notation such as 4/4 and 8/4 describes hardwood thickness classes. S2S, S3S and S4S usually indicate surfaced faces or edges, but the resulting dimensions and seller usage require confirmation. Nominal sizes such as 2 × 4 are names, not guaranteed measurements.
Log-rule labels
Doyle, Scribner, Scribner Decimal C and International ¼-inch must remain explicit. “Log BF” without a named scale is incomplete. Include small-end diameter inside bark and the table or edition when a figure must be audited.
A safe notation pattern
Write a value as “2.5 MBF (2,500 board feet; nominal tally basis)” or “180 BF estimated by International ¼-inch, 16-inch DIB × 16 ft.” The expanded wording carries the convention, basis and model with the number.
Questions about this topic
What does DIB mean?
Diameter inside bark; log records should also state where the diameter was taken.
Is FBM different from BF?
It commonly means board-foot measure, but define it in the document.
What does 4/4 equal?
It identifies a four-quarter thickness class; do not assume every physical board measures exactly one inch.
Related BoardFoot Bench pages
Method and content reviewed 3 September 2026.