Large packages sent via freight on trucks or airplanes are charged based on the size, weight and density of the item being shipped. To help standardize freight shipping rates, the National Motor Freight Traffic Association (NMFTA) created the National Motor Freight Classification (NMFC). If you are sending large shipments via freight, you’ll need to find your NMFC number to determine the most accurate pricing.

Factors Determining the NMFC Number 

The NMFC created freight classes based on the density, handling, stowability and liability of the item being shipped. Density accounts for the weight per cubic foot. Handling is determined by qualities of the item being shipped that make it unique, such as hazardous or fragile materials. Stowability is based on the ease of loading the item with other freight; liability considers the value and the chance of damage or theft.

Once these four factors are taken into account, the item being shipped is assigned to one of 18 classes, ranging from class 50 to class 500. These classes help a freight transport provider determine how much to charge for shipping.

Keep in mind that, despite the class, you can always try to negotiate the price of shipping with the transport provider. The NMFTA itself says the NMFC "provides both carriers and shippers with a standard by which to begin negotiations."

Finding the Correct NMFC Number

To find the NMFC number that applies to your specific shipment, consult with the freight company you are using to ship your package. It will be able to help you classify your shipment and determine shipping costs.

Keep in mind that only those transport providers using provisions of the NMFC in their business dealings are required to participate in the classification system. Transport providers that do not include in their contracts, rate schedules or tariffs provisions of the NMFC — such as packaging specifications, classes and rules — do not have to abide by the provisions of the NMFC and can set rates as they see fit.

If you’d prefer to calculate the NMFC number on your own, you can contact the NMFTA’s Commodity Classification Standards Board via the NMFTA website. You can also get an estimate of freight class and shipping costs using the FedEx Freight Classification tool. By entering the category and dimensions of the item you are shipping, you will receive an estimated freight class.

Importance of the NMFC Number

No matter how you go about finding the NMFC number that applies to your interstate, intrastate or foreign shipment, you should obtain one to make sure you are being fairly charged to ship your item. Without one, you won’t have a baseline for determining if you’ve been overcharged for shipping.