Knowing your freight class is essential for LTL (Less Than Load) shipping because it dictates pricing. But what is it and what factors determine it? Is there an easy way to find out the freight class of a shipment? Below we’ll give you an in depth look into freight class.
What Is a Freight Class?
The first step in figuring out your shipments freight class is understanding the freight class definition. The National Motor Freight Traffic Association defines a freight class as the measure of a shipment’s “transportability.” Meaning, how easy it is to ship that commodity from one place to another.
Freight class is an important part of LTL shipping because it determines the price of the shipment, taking into account not only shipping rates, but also tariffs and added fees. Trying to lie about the class of your items might be tempting, but will not be successful, as the items will just be re-classed. The National Motor Freight Classification (NMFC) has 18 classes that an item or shipment can be grouped into.
Factors that Determine Freight Shipping Class

There are four factors the NMFC uses to determine the freight class of a shipment:
- Density
- Stowability
- Handling
- Liability
Density
An object’s density is calculated using the dimensions and weight of the item; for shipping purposes, density is measured in pounds per cubic foot. It sounds confusing but the higher the density of the item, the lower the class, and the lower the price of shipment.
Most companies prefer to ship small, heavy things because they don’t need much room and more products can be shipped in one load. Keep in mind that some commodities are not classified by density and have pre-determined classes.
Stowability
Stowability is how the items being shipped can be arranged within the transport vehicle or train in relation to other items. Shipments with weight, dimensions, or shape that are out of the ordinary are more difficult to stow. Stowability also takes hazardous shipments into account. Shipments should have noticeable load-bearing surfaces to allow for easy stacking with other goods. The more difficult it is to arrange the shipment with others, the higher the freight class and the greater the cost.
Handling
Handling is the measurement of how difficult it is to handle a shipment as it is being loaded or unloaded at terminals, checkpoints, and distribution centers.
The fragility of the item, how well (or poorly) it’s packaged, and its dimensions are all considered when determining how to handle it. The more difficult it is to carry and handle the item, the higher its freight class.
Liability
Liability concerns the probability of a shipment being stolen, damaged, or damaging other items surrounding it. For example, perishable items and combustible materials are considered a greater liability to the freight shipping company and therefore have a higher freight class.
Freight Class Based on Density - The Main Determining Method
For most shipments, the main determining factor for freight class is density, assuming the package being shipped does not have significant liability, stowability, or handling concerns. The specific guidelines that determine freight class based on density ignore issues related to stowing, handling, and liability and assume an average uniform density of items within a class.
Organizing freight class by the type of item being shipped is inherently flawed. Not every item with the same name is created equal— they could have different weights and shapes. For example, a television can come in many different sizes and weights, and it would not make sense to group them in the same category.
Grouping commodities by density might seem inconvenient for manufacturers that are shipping multiple truckloads of items, but using true density eliminates the possibility of disagreements between shippers and carriers on NMFC codes and pricing.
Though generally, density is the primary factor dictating freight class, it is important to remember that stowability, handling, and liability will still be taken into account.
How to Calculate Your Freight Density
Calculating the density of your freight is not a complicated process, just follow the steps below:
- Measure the height, length, and width of your item, and be sure to round up to the next inch, if necessary. Include pallets and any other packaging surrounding the item in these measurements. Shipments with more than one item will need to repeat this process for each item.
- Multiply the height, length, and width measurements together to determine the total cubic inches of your shipment. In order to convert cubic inches to cubic feet, take that number and divide it by 1,728. With shipments of multiple items, multiply the measurements for each item and add them together before converting to cubic feet.
- Find the weight of the shipment in pounds and divide it by the total number of cubic feet to determine the density in pounds per cubic foot. If you have a shipment with more than one item, add up the weight of each of the items before dividing by the number of cubic feet.
- Now that you have solved for your shipment’s density, consult the LTL freight class chart to identify the freight class of the shipment.
Dependence on The Freight Class When It Comes to Quotes

The price of shipment is directly correlated with a freight class. If the freight class is lower, so is the price. An item that is class 400 will cost significantly more to ship than an item that is class 60.
Freight Class Chart and NMFC Code List Lookup
Below is a chart of the 18 different types of classes, numbered 50 to 500, that the NMFC divided by density. In the table, there are examples of items that can be found in each class.
Keep in mind that these are estimates that are fairly accurate but stowability, handling, and liability also play a part in determining freight class and cost of shipping. Use a freight class calculator or check with your LTL shipper to see their specific guidelines on freight classifications.
What Are National Motor Freight Classification Codes?
A National Motor Freight Classification NMFC code is not so different from the PLU number you find on produce in the grocery store. Every LTL item shipped is assigned an NMFC code and items within the same class have different codes. For example, bricks and hardwood flooring are both in freight class 50, but bricks are assigned NMFC code #32100.2 and hardwood flooring is assigned #51200.
These codes can be easily accessed in the NMFC database, which is consistently being updated. Finding the NMFC code for your shipment is how you will determine its freight class. While some items have an established, permanent class, others might need to be classed based on the previously discussed factors (stowability, handling, density, and liability.)
How Do You Find Your Correct Freight Class or NMFC Code?

Now that you know what a freight shipping class is, how to calculate it, and how it will affect the price of your shipment, the last step is to learn how to find the correct freight class. Many websites online have freight class calculators and many carriers and freight brokers have their own calculators as well. It is important to remember that these calculators are meant to be convenient for the occasional shipper and only give estimates of classes.
Your LTL shipping expert has access to the NMFC database and can give you the correct NMFC code for your items, which will allow you to confirm that your shipment’s freight class is correct. To avoid confusion and reclasses, be sure to make the code and class visible on the bill of lading.
Tips and Tricks
- Include a description of the freight on the BOL (bill of lading), and make it as detailed as possible. If the freight description says something generic like “shipping item”, it could be re-classed because the carrier won’t know what it is and how to classify it correctly.
- Research the carrier you will be using, they are not all the same! Some are more particular than others, so make sure you know their habits.
- Remember that online classification calculators are just an estimate. Though they will give you an accurate density of the shipment, every item does not have a density-based class.
- Don’t try to cheat! You will not be able to fool the freight shipping companies and you will be left paying the price for the necessary re-classifications.
- Never forget to clearly put the NMFC code on the BOL so the carrier can’t miss it.
Conclusion
If you need assistance with your shipment’s NMFC codes or freight classification, get a quote from freight shipping company and speak with one of our shipping experts.