Freight density vs. freight class
Density does not determine freight class by itself. Density is a measurement you can calculate from a shipment's weight and dimensions. Freight class is a classification assigned under the National Motor Freight Classification (NMFC), which is published by the National Motor Freight Traffic Association (NMFTA).
What density is
Density is weight divided by volume, in pounds per cubic foot (PCF). Anyone with a tape measure and a scale can calculate it. Use the freight density calculator to do it.
What freight class is
Freight class is the category the NMFC assigns to a commodity. The classification is maintained by NMFTA, and the carrier applies it together with its own rules and your agreement with that carrier.
What changed in 2025
NMFTA announced changes to the NMFC that took effect on July 19, 2025, including an expanded density scale for classifications that are based on density. See NMFTA's explanation for shippers.
Why density alone is not enough
An expanded density scale does not mean every commodity is classified by density alone. A density figure tells you how heavy a shipment is for the space it takes. It does not tell you which NMFC item applies to your commodity, or how your carrier measures and inspects freight.
Where to confirm a class
Confirm the classification with NMFTA's official tools or with your carrier or broker before you put a class on a bill of lading. FreightTools does not publish a class table and does not certify classification.
Sources
- How Shippers Can Prepare for the 2025 NMFC Changes. National Motor Freight Traffic Association (NMFTA). Accessed 2026-11-12.