Almost all U.S. LTL carriers use NMFC freight classes, although some are attempting to move to a dimensionally-based system.
Every commodity has both a freight class and a NMFC code. Freight class represents a category of items while NMFC codes relate to specific commodities within each of the 18 freight classes.
NMFC freight subclasses are used to differentiate among commodities of the same type. For example, one NMFC code for chairs/stools is 82790. Subclasses 82790-1 and 82790-11, despite have the same base NMFC code, fall into two different freight classes.