The Standard for Freight Identification and Classification
The National Motor Freight Classification (NMFC)® is a standard that provides a comparison of commodities moving in interstate, intrastate and foreign commerce.
For more in-depth training, please visit: https://nmfta.org/nmfc/training/.
What Is a Freight Class?
A freight class is provided by the National Motor Freight Classification (NMFC), which is a classification used by transportation companies for less-than-truckload (LTL) freight shipments. Freight classes range from 50-500, and classification levels are determined by four transportation characteristics. Those characteristics are handling, stowability, and liability, discussed in further detail below. Denser and easier to handle and stow loads receive lower classification numbers, while less dense and more difficult-to-handle loads are classified with higher numbers. Cargo with liability concerns can also receive higher classification numbers.
How to Avoid Freight Class Mistakes
Use a trusted, comprehensive source to determine your specific freight classes to avoid unintentional freight classification mistakes. The National Motor Freight Traffic Association's ClassIT tool helps users determine the correct NMFC item number and associated freight class. When calculating density, it's important to make sure the freight's weight and dimensions are accurate and not based on estimates alone.
Why Does Using the Correct Classification Codes Matter?
The NMFC system is in place to define standard freight classes for the goods being transported. It sorts freight into several categories, which are continuously amended by the National Motor Freight Traffic Association™ (NMFTA™). Through this scale, everyone in the LTL supply chain has a standard system to identify and classify freight which lets LTL shipments proceed smoothly.
It is important to identify and label the correct freight class when shipping cargo to ensure the transportation process is safe and efficient. If cargo is labeled as the wrong freight class, this can interfere with a carrier’s ability to estimate the difficulty of moving a shipment.
In general, lower freight classifications equal lower shipping costs, while higher classifications result in higher shipping costs. If you accidentally use a lower freight class and your less-than-truckload carrier determines that the class should be higher and reclassifies the freight, the shipper may incur additional charges.
Using the correct classification codes is also important to ensure the safety of personnel and the integrity of the freight. NMFC codes identify cargo based on a number of criteria. For example, refrigerated goods, hazardous materials, and delicate electronics are three types of freight that need to be handled differently than most cargo. If they are mislabeled the result could be spoiliage, other damage to the goods, or danger to the personnel handling them.
In order to ensure the integrity of freight and efficiency when shipping goods, it is important to properly label shipments with the correct classification codes. Likewise, following proper freight packaging guidelines is important for smooth delivery.
What Factors Determine NMFC Codes?
The NMFC assigns a freight class based on four criteria:
- Density
- Handling
- Stowability
- Liability
Based on a combination of these characteristics, a freight shipping class is assigned, ranging from 50 to 500. There are 18 separate classes ranging within these values, with lower numbers indicating cargo that is relatively easier to ship. Freight that is in a higher freight class, typically is more difficult to ship.
The weight that each factor has in determining the freight class depends on the type of cargo. Below, each factor is analyzed with examples given to show how a shipment may be classified under the NMFC codes.
Density
Freight density is a measurement of how much space cargo takes up as well as how tightly packed it is relative to its size. This measurement is calculated by taking the cargo's total cubic feet and dividing by the weight of the cargo. The result gives the freight's density, measured in pounds per cubic foot.
For LTL carriers, a cargo's density matters when considering how to allot space in the trailer. Cargo with a higher density is typically easier to ship and is assigned to a lower freight class. This is because more dense fright is generally easier for a carrier to efficiently pack into a trailer. Some examples of cargo with high density that would be assigned a lower shipping class include the following:
- Nuts and bolts
- Bulk ingredients
- Bricks and cement
- Car parts
- Books
On the other hand, some items that are less dense and would be assigned a higher shipping class could include:
- Ping-pong balls
- Kayaks
- Wood cabinets
- Mattresses, tables and assembled chairs
Handling
This is a measurement of how easily freight can be handled, with bulky and larger cargo often being categorized in a higher shipping class. Some examples of cargo that might be assigned a high freight class include loose, large car parts; sofas; and any number of other oddly-shaped items.
Other items may be in a higher class based on special protocols that must be followed when handling them. For example, corrosives and other hazardous materials require special training and care when shipping. Sensitive electronics or highly fragile items, such as large instruments, may also be assigned a higher class.
Some examples of easy to ship cargo might include anything that fits in a reasonably sized cubic or rectangular box and isn't too heavy. Shipments that come in boxes will usually not have handling concerns.
Stowability
Freight stowability is a consideration of how easy it is to stow cargo on a trailer. Items that are easily stowed are those that come in uniform shapes and sizes, such as a box of nuts and bolts or a bulk shipment of similarly-sized items.
Items with stowability concerns are those that are difficult to stow due to their size or shape. For example, a large sofa, a rolled-up mattress or rug, loose automotive parts or any other non-uniformly shaped item will be assigned a higher shipping class. Freight carriers will have to sacrifice space on the trailer for items like this, so they have to charge more to ship them.
Liability
Within the freight industry, some items carry a certain amount of liability to ship. While some items are harmless, LTL carriers often transport hazardous materials of various kinds. Materials such as firecrackers, corrosive materials and other flammables all pose a risk of endangerment and are considered to have liability concerns according to NMFC guidelines.
How To Determine Freight Classification and NMFC Codes
With all of the commodity types that are shipped every day, it is important to know how to determine the freight class of your cargo. NMFTA tools such as ClassIT contain all the freight classification codes, where you can look up any commodity you might be moving. To get the most accurate freight class, be sure to search for specific words in the database to find your product.
You can measure your item’s density on your own if your NMFC item number provides different classes based on the final density of the shipment. ClassIT also provides calculators to help with this.
NMFC Resources
- Who Must Participate
- NMFC Standards
- Freight Classification Development Council (FCDC)
- Amending the NMFC
- NMFC Changes 2025: How Shippers Can Prepare
- NMFC Changes 2025: How 3PLs Can Prepare
- NMFC Changes 2025: How Carriers Can Prepare
- Classification Resource Committee (CRC)
- Classification Assistance & Interpretations
- Classification Research Projects
- Packaging
- Training and Education
- Video: How to Class Freight
NMFC Products
Membership is available only to for-hire interstate and intrastate motor carrier participants.
