The NMFC is the rulebook for LTL freight classification. Without it, LTL pricing would be inconsistent between carriers and commodities — each carrier would develop their own classification system. The NMFC provides a uniform standard that all participating LTL carriers use as the basis for rate calculation.
The classification is organized by item number, not commodity name. A specific commodity may have multiple NMFC item numbers depending on packaging, condition (new vs. used), or intended use. Finding the correct item number requires searching the NMFC directory by commodity description, not by product name.
NMFC items specify a freight class, or a class table where the class varies by density. When a density-based class table is specified, the shipper must calculate the density of their shipment (weight divided by cubic feet) and find the corresponding class in the table. This calculation must be done per-pallet or per-shipment, depending on how the commodity is packed.
NMFC access is through subscription to the NMFTA's ClassIT tool or through freight broker and carrier portals that include classification tools. Some carriers also maintain online classification lookups. For shippers who regularly ship LTL with standardized commodity types, the time invested in determining the correct NMFC item number pays off in billing accuracy and avoidance of reclassification charges.
The NMFC is updated periodically. Items are added, modified, and occasionally reclassified as commodities change and carrier operating experience accumulates. Shippers should verify their commodity classifications against the current edition, particularly after packaging or product design changes.