Freight Shipping 101 Series: How Do You Determine NMFC Freight Class?

(1st in a series of 5 posts)

In the world of LTL Freight shipping it’s the question of the ages: “what is my freight class?”. There is confusion around what class is, what it means and how to find it for a specific commodity. In this post I will aim to tackle all three and set you on your merry way ready to ship freight like a champ.

What is an NMFC Freight Class?

In the US, each “commodity” (or type of product) is assigned one of 18 classifications from the lowest 50 (good/inexpensive) to highest 500 (bad/expensive) which determines the cost of the shipment. Classes are based on an evaluation of four transportation characteristics: density, handling, stowability and liability. Combined, these characteristics establish a commodity’s “transportability.” It is important to determine the correct one to avoid a host of potential issues such as “reclassifications” and denied freight claims which can result in expensive headaches.

How do I determine Freight Class?

Freight classes are defined by the National Motor Freight Traffic Association (NMFTA) and made available through the NMFC or National Motor Freight Classification system. If you are reading this you likely are not a registered freight carrier or logistics company so you will have to ask one (like us, wink) or purchase the book or a service plan on the NMFTA website. But, once you have your item numbers locked in they very rarely change and a good broker or carrier will let you know when they do.

In recent years, the governing body in charge of the NMFC (called the CCSB) has moved towards a sliding “density-based” scale to determine freight class. This scale defines classes according to their density in lbs per cubic foot or PCF. This protects both carriers and shippers from being exploited by an outdated classification that does not take into account the specific shipment’s density profile, a pillar of freight classification

Plastics, NOI (density based) item screenshot from the SMC3 online system.

Plastics, NOI (density based) item screenshot from the SMC3 online system.

An example of a density based item is the catch-all for “Plastics, NOI” item# 156600. If your item # is density-based you’ll want to have a density calculator handy so you can make quick calculations to get accurate freight quotes. If you need one or want to see an example click on our density calculator or click the contact us button and we’ll send you an excel spreadsheet version.

Accurate classification will require the nature of the commodity, including the following:

  • Its use or function

  • Its material construction

  • How it is represented for sales purposes and recognized in the trade

What Does Freight Class Mean?


The NMFC freight class system is a standardized method designed to give shippers a uniform pricing structure when transporting freight. Besides determining the cost of a freight shipment  the freight class also helps LTL carriers determine it’s liability or susceptibility to damage. Yet another reason the class is important, many carriers offer different liability (insurance) levels for the different classes. Moving a shipment under the incorrect class could result in a lower claim payment in the event of a loss or damage.

Be sure to read your item and notes carefully as there can be exclusions such as length, value and packaging. If you have any questions ask your broker or carrier before shipping to avoid any potential issues. It is very important to have a solid grasp on your item# and class as classification changes can result in large invoice discrepancies and lengthy disputes with carriers. To avoid any potential headaches and issues, feel free to reach out to us by filling out our contact form and we will determine your freight class for you and provide item screenshots for your reference.