Freight class, or NMFC (National Motor Freight Classification), is a shipping industry standard and grouping system. It’s used for interstate, intrastate, and foreign commerce movement of LTL (less than truckload) shipments. 

What is the purpose of Freight Class?

The intention behind NMFC is to provide a standard comparison of commodities for freight identification and classification. This is necessary for simplifying comparative evaluations of the billions of different products annually shipped within today’s globally competitive market. By providing a definitive source of common ground between shippers and carriers, this system helps facilitate smooth and productive freight rate negotiations and logistics.

Who must participate in the NMFC?


Transportation companies that use or reference in their contracts, rate schedules or tariffs any provision of the National Motor Freight Classification—including commodity descriptions, classes, rules, packaging specifications and bills of lading—must participate in the NMFC®. The provisions of the NMFC have no application for transportation companies that do not participate.                        


Participation in the NMFC is established by the completion of a license agreement and payment of an annual fee. Participants are issued a certificate of participation by NMFTA. Purchase of the National Motor Freight Classification, or assignment of a Standard Carrier Alpha Code (SCAC®), does not satisfy the requirement for participation.


For more information on NMFC participation or to become a participant, please contact NMFTA Customer Service at 866-411-6632.

How do I determine Freight Class?

Freight class describes a commodity’s overall “transportability.” The four primary metrics used to calculate transportability are:

  1. Density
  2. Ease of handling
  3. Liability
  4. Stowability

 *Distance, volume, and other market factors may also inform how your freight is classified.


Within the shipping realm, density is defined as the space an item occupies in relation to its weight. Regarding class: Class 50 (lowest class) is assigned to freight that is greater than 50 lbs. per cubic foot. On the other end of the spectrum, at class 500, we see freight that is less dense than 1 lb. per cubic foot (gold flakes, for example).

Ease of Handling

Most cargo is simple to load and unload, especially when these tasks are doled out to machinery, as they often are. Still, there is freight that requires special care and attention due to restrictions brought upon by irregularities in weight and/or shape, excessive fragility, or hazardous properties. These sorts of restrictions may warrant a change in freight classification.


Heightened risk of theft or accidental damage is considered when leveraging accountability.  Perishable items and dangerous chemicals, for instance, carry potential liability concerns and costs.


Some types of freight are subject to government regulation or specific carrier policies. There are several freight types that cannot be loaded together, such as certain hazardous materials, freight that is particularly massive, or that protrudes in a fixed, inconvenient direction. Freight class attempts to quantify relative stowability to reflect how easy or difficult it is to handle various kinds of freight.

Step by Step Instructions for Calculating Freight Density:

  1. Determine the length, width and height of your freight in inches (Including packaging).
  2. Multiply these three metrics to calculate the size of your freight in cubic inches.
  3. To convert to cubic feet, divide this by 1,728 (the number of cubic inches in a cubic foot).
  4. Then, divide the weight of your freight (in pounds) by the total cubic feet.
    This will give you the density of your freight.
    L x W x H = inches3 # inches3 / 1,728 = feet3weight in lbs./ feet3 = density

Please also see the following link to an online calculator for easy determination of Freight Class:

Freight Class Calculator