Freight Class Explained: Categories, NMFC Codes & Costs

 

Any company that sources materials, manufactures goods or ships products to consumers must consider how they get those products into their customers' hands. Working with a transportation management partner can help optimize these decisions. More importantly, they must take into consideration the costs involved.

One of the things that help determine shipping costs is the freight class that the products fall into.

Getting your freight class right is critical. Get it wrong and you risk losing money, customers, and causing unnecessary shipping delays.

So, what are freight classes, and how are they categorized? In this blog post, we'll explain the National Motor Freight Classification system and break down the four key categories that determine your freight class.

National Motor Freight Classification (NMFC)

To help shippers determine their freight class categories when getting ready to ship their goods, the National Mode of Freight Traffic Association (NMFTA) sets the standard for how they are determined. These classes are then made available to all supply chains via the National Motor Freight Classification (NMFC).

In fact, all carriers should be able to provide a chart of these freight classes upon request.

Currently, there are a total of 18 types of freight classes, each with their own subgroups. These classes are numbered from 50 to 500, with lower numbers indicating denser, easier-to-ship freight.

When the NMFC compile these freight classes they give each class a unique code—and these codes can shift as NMFC updates take effect. Each of the 18 freight classes gets assigned a number ranging between 50 – 500.

This is the commodity number. It is this number that shippers place on the BOL so as to allow the carrier to easily identify what the package contains. Essentially, this number helps expedite the classification process and in-turn, the shipping speed.

Furthermore, the numbers are associated with 1 of 4 categories:

  • Density
  • Stow-Ability
  • Handling
  • Liability

The NMFC Commodity Number Categories

A list of these freight class categories can also be found on the NMFTA Website. And most of the time, carriers supply their clients with this information, usually upon request.

Density

Density, with its groups and sub-groups, indicates that the goods fall into a density-based class. This is clarified in the NMFC table.

If you ever need to ship via a density-based class, it is actually fairly simple to calculate the cost.

First, we take the measured weight of the item in pounds and the physical volume (length x height x width) measured in inches. We then divide that number by 1728. This result divided into the weight of the item (expressed in pounds) provides the "pounds per cubic foot" or PCF value.

It sounds more complicated than it actually is!

Stow-Ability

In general, most items are stowable. These items are ones which stow well in trucks, trains, or boats. This category considers the actual shape and stability of the goods versus their density.

This category indicates to the carrier that the goods are easily stackable, contains no protruding parts, and are too large for more standard shipping modes.

Handling

Some items only require standard carrying procedures. But some, due to weight, shape, fragility or hazardous properties require special handling.

Classification of special treatment represents the difficulty in loading or carrying the item(s) which if applicable, again will incur extra handling costs.

Liability

This category indicates more precious items that may be susceptible to freight theft or might damage adjacent freight during transport.

Perishable cargo, freight prone to tip, spontaneous combustion or explosion is also classified based on liability and assigned a value per pound of goods transported. This is usually just a fraction of the liability of the carrier.


Final Thoughts

Without this knowledge, shippers run the risk of overpaying or even overestimating costs based on the wrong classifications. A proactive shipment management review can help catch these errors before they add up.

FAQ

What is freight class in shipping?

Freight class is a standard used to categorize freight for pricing and handling purposes, especially in less-than-truckload shipping. The National Motor Freight Traffic Association sets the classification through the National Motor Freight Classification, or NMFC. Freight classes run from 50 to 500, with lower numbers generally indicating denser, easier-to-ship freight.

How are freight classes determined under NMFC?

Freight classes are determined under the NMFC using four main factors: density, stow-ability, handling, and liability. Each commodity is assigned a class number and commodity number that carriers use to identify it on the bill of lading. Those codes can change as NMFC updates take effect, so classification needs to stay current.

What does density mean in freight class calculations?

Density refers to how much weight fits into a given volume, and it is one of the key freight class factors. To calculate it, measure the item’s weight in pounds, calculate the cubic volume in inches, divide by 1,728 to convert to cubic feet, and then use that result to find pounds per cubic foot, or PCF.

What do stow-ability, handling, and liability mean in freight class?

Stow-ability looks at how well freight fits and stacks in trucks, trains, or boats. Handling considers whether the item needs special care because of its weight, shape, fragility, or hazardous properties. Liability addresses items that are more likely to be stolen, damaged, or harm other freight, including perishables and freight prone to tipping or combustion.

Why does getting the wrong freight class matter?

Getting the wrong freight class can cause you to overpay, underestimate shipping costs, face delays, and create customer dissatisfaction. Incorrect classification can also lead to disputes because the class number affects how carriers price and process freight. A proactive shipment management review helps catch these errors before they add up.

Where can shippers find freight class information?

Shippers can find freight class information through the NMFTA and from carriers, who should be able to provide a freight class chart upon request. The NMFTA website also lists the commodity number categories used in the NMFC system. These references help shippers classify freight more accurately before it moves.

What is a commodity number on a bill of lading?

A commodity number is the code placed on the bill of lading to help the carrier identify what the shipment contains. It supports the freight classification process and helps speed up identification and shipment handling. In the NMFC system, each class is associated with a commodity number that can shift when updates are released.