Freight class is a standardized classification system used to determine how much your freight should cost to ship based on a number of factors. The freight class of an item is determined by many factors such as: Type of Product, Value of Product, Ease of Handling and Liability. The freight classes go from 50 to 500, 50 is cheapest, 500 is most expensive. The NMFC (National Motor Freight Classification) system is what is used to determine your items class. The best way to determine your freight class is to call an LTL carrier.