The National Motor Freight Traffic Association (NMFTA) publishes a list of freight class designations, codes, and subclasses for commonly shipped items (https://classit.nmfta.org/). A subscription fee is required to access this list. You can learn more about freight classes from the experts at Koho for free on our freight classes pages.
Working with a 3PL like Koho can help you accurately determine your freight class so you can avoid re-classification fees with the carriers. For more information on the freight class system, go to the National Motor Freight and Traffic Association.
No. While density is one of the primary factors in determining NMFC freight class, other factors, such as value, are also used in making that determination. Gold bars, for example, are very dense, but they fall into shipping class 500 along with very low-density items because of their high value.