The National Motor Freight Classification (NMFC) is the freight classification system devised by the National Motor Freight Traffic Association (NMFTA) and is used for all interstate, intrastate, and foreign commercial movement of LTL cargo. NMFC codes provide standardized freight classes to determine the ease of transport of many of the wide variety of commodities that are shipped together in LTL shipments.

It might be tempting to declare that your shipment is a lower freight class than it actually is in order to secure a lower price, however, carriers will re-classify your freight for accuracy and charge you a fee for having to do so.

Some items, such as car transmissions, have a specific class no matter how heavy or big they are. This is called a fixed class. Items can be assigned a fixed class if the value and transportability very rarely change.