Created and maintained by a nonprofit organization called the National Motor Freight Traffic Association (NMFTA), National Motor Freight Classification (NMFC) is a classification system used for interstate, intrastate, and foreign commerce movement of LTL shipments. You can learn more on our freight classes pages.

Adding NMFC code to a shipment is technically optional, but the NMFC codes can help avoid reclassification and ensure you're using the correct freight class number.

Density is the relationship between weight and size. A ping pong ball, which is very little material surrounding a good amount of air, is low density. Bricks, which are heavy for their size, are high density. In LTL shipping, it is commonly measured in pounds per cubic foot.