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What is freight class?

Last reviewed by José Luis Pérez

Freight class is the category an LTL commodity is assigned under the National Motor Freight Classification (NMFC), published by the National Motor Freight Traffic Association (NMFTA). NMFTA assigns each commodity a class from 50 to 500, and carriers use the class, together with their own tariffs and your agreement, to price the shipment.

The four characteristics behind a class

NMFTA bases freight class on four transportation characteristics:

  • Density: how heavy the freight is for the space it takes up.
  • Handling: how easy it is to move across a dock and into or out of a trailer.
  • Stowability: how effectively it can be stowed in a trailer.
  • Liability: how likely it is to be damaged or to damage other freight.

In NMFTA's words, "The denser and easier to move, the lower the class—and the lower the cost."

Lower class, higher class

Classes run from 50 to 500. A lower class generally means freight that is dense and easy to handle; a higher class, freight that is light for its size, fragile or awkward. Because the class feeds the rate, an incorrect class on the bill of lading can lead to a reclassification and a higher invoice. See LTL reweigh and reclassification.

What changed in 2025

NMFTA's changes took effect on July 19, 2025. According to NMFTA:

  • the 11-sub density scale was replaced by a more detailed 13-sub scale;
  • over 2,000 items moved to full density-based classification;
  • many generic NMFC headings were consolidated;
  • items with unique handling, stowability or liability considerations are marked clearly.

More items now depend on density, so accurate dimensions matter more than before.

How to find your freight class

  1. Identify the commodity precisely, including how it is packaged.
  2. Find the NMFC item that covers it. See NMFC codes.
  3. If the item is classified by density, calculate the density of the shipment with the freight density calculator.
  4. Confirm the class with NMFTA's tools or with your carrier or broker before you put it on the bill of lading.

What FreightTools does not do

FreightTools does not publish a class table and does not assign or certify classes. Density is a measurement; class is a classification that depends on the NMFC item, its rules and your carrier's tariff. See freight density vs. freight class.

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