Freight Class and NMFC Code Basics

A shipper’s guide to NMFC codes and freight classification 

There are plenty of industry-specific terms in logistics, but one you’ll hear often when quoting or booking less-than-truckload (LTL) freight is National Motor Freight Classification (NMFC^®). This system determines a shipment’s freight class, which plays a role in how much you pay to ship something. If you’ve ever been surprised by a rate or fee, there’s a good chance classification had something to do with it.

With the recent updates that took effect on July 19, now is a good time to revisit how the system works, what changed and why it matters.

Freight classes explained

Freight class is a standardized way to categorize goods shipping LTL. These classifications are set by the National Motor Freight Traffic Association (NMFTA) and are based on four factors:

•  

  Density:
  The weight-to-volume ratio of the item

• Handling:
  How difficult it is to manage during transport

• Stow ability:
  How easily the item fits with other freight

•  

  Liability:
  Risk of damage, theft or value-related concerns

Together, these factors determine how complex it is for a carrier to transport your freight. 

But how does freight get classified? That’s where NMFC codes come in. The NMFC system assigns a unique code to different commodities, and each code corresponds to a freight class.  

What changed in July 2025?

The NMFTA implemented a new 13-tier density-based classification scale, replacing the previous 11-class system. This update continues to prioritize density over the other three factors. Moving to a simpler system makes things easier for carriers and 3PLs and improves pricing accuracy for shippers.

The update also includes consolidating many commodities into more universal broad categories, flagging for freight that requires special handling and launching the NMFTA’s new online classification tool, ClassIT+.

New 13-Tier NMFC density scale

Subclass	Freight Density (in lbs per cubic foot)	Freight Class
Sub 1	Less than 1	400
Sub 2	1 but less than 2	300
Sub 3	2 but less than 4	250
Sub 4	4 but less than 6	175
Sub 5	6 but less than 8	125
Sub 6	8 but less than 10	100
Sub 7	10 but less than 12	92.5
Sub 8	12 but less than 15	85
Sub 9	15 but less than 22.5	70
Sub 10	22.5 but less than 30	65
Sub 11	30 but less than 35	60
Sub 12	35 but less than 50	55
Sub 13	50 or greater	50

Why NMFC codes matter

An accurate NMFC code is necessary for several reasons:

• It impacts the price. Using a correct NMFC item number will help ensure the quote matches the price on the freight invoice.

• It determines liability coverage. Some carriers offer higher liability limits for higher-class freight.

• It helps ensure shipments are handled appropriately. How loads are comingled, secured, stacked and protected can change based on the NMFC.

• It alerts carriers to special requirements. Things like sensitive electronics, medical supplies, pharmaceuticals and hazardous materials may require special license endorsements, placards and equipment types.

 If you don’t provide the correct information on your bill of lading (BOL), a reweigh or remeasurement that changes the class or NMFC code can lead to additional fees and delays.

How to classify your LTL shipment under the new system

Correct freight classification is more important than ever. Here’s how to make sure you’re using the correct codes:

Capture accurate dimensions

Having precise dimensional data is critical. Make sure your team records and includes length, width, height and weight for each shipment on the bill of lading. Learn more about the importance of measuring LTL freight.

Use a lookup tool

Talk to your ArcBest account manager to learn about the options and tools available to help you locate the NMFC Item Number and Freight Class. Don’t have an ArcBest account yet? Click here to get started!

You can also find a specific NMFC code using the NMFTA’s classification tool, ClassIT+.

Revise any stored codes

Review and update any NMFC codes saved in your TMS, ERP or WMS platforms to reflect current classifications.

Consider your packaging

With the updated density-based structure, it’s incredibly important to pay attention to packaging. Overpackaging can lead to bulkier, lower-density freight (which means a higher class and possibly higher rate). On the other hand, compact packaging can increase density, lower your class and reduce your rates.

ArcBest has packaging engineers available to help optimize your packaging for both protection and performance. They work with shippers to build strategies that reduce damage, improve handling and maximize trailer space.

Need help understanding the NMFC classification system? 

Whether you need help reviewing your current freight classifications, updating your systems or figuring out how to get better rates with a new freight class, ArcBest is ready to support you. Let’s work together to ensure your freight is classified correctly and your shipping strategy stays efficient and cost-effective.

Want more information about the changes? Watch our webinar “From Confusion to Confidence: Preparing Your LTL Strategy for the NMFC Changes.”