The National Motor Freight Traffic Association (NMFTA) created the National Motor Freight Classification (NMFC). It is used for all interstate, intrastate, and foreign commercial movement of LTL cargo. NMFC codes provide standardized freight classes to determine the transportability of the large variety of commodities that are shipped together in LTL shipments every year.
The first step in determining your freight class is to take measurements. Measure the height, width and depth of your shipment then multiple those three measurements together for the total cubic feet. Then divide the total cubic inches by 1,728 (the number of cubic inches in a cubic foot). Finally, divide the weight (in pounds) of the shipment by the total cubic feet.
NMFC freight classes are determined using four factors: density, handling, stowability, and liability. All of these factors affect the cost to the carrier of shipping goods.