An organization called the National Motor Freight Traffic Association (NMFTA) publishes a list of freight class designations, codes, and subclasses for many frequently shipped items (https://classit.nmfta.org/). To view this list, you must pay a subscription fee. Learn more about freight classes from the experts at Koho for free on our freight classes pages.
The National Motor Freight and Traffic Association has 18 freight classes numbered 50 to 500. The lower the freight class, the lower the cost of transporting that freight.
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.