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What Is Freight Class, how it is Determined and Calculated?


If you were a shipper, you would have heard about freight classes, and it might have sounded complex. You might have pondered to know about freight class, how it is determined, and how it impacts shipping costs. If these questions are bothering you, then you have landed on the right page. This blog provides a clear guide on the concept of freight class, how it is determined and calculated, and empowers you to make an informed shipping decision.

What is Freight Class?

Freight class is a standard classification system used by Less than a Truck Load (LTL) carrier to categorize shipments based on their characteristics. There are 18 different classes ranging from 50 to 500 in the NMFC (National Motor Freight Classification) system which was established by the NMFTA (National Motor Freight Traffic Association).

How to Determine Freight Class?

Unique code like a UPC or PLC code assigned for your LTL shipment based on the characteristics of the commodity like lightweight, dense, low risk while transporting, etc. Once you have the NMFC code, you can look up the corresponding freight class in the NMFC.
To find the exact NMFC code of your shipment, you can use the NMFC book also known as the ClassIT tool by NMFTA. The NMFC book is a comprehensive document that lists over 18,000 commodities and their corresponding NMFC codes.
The NMFC system determines the freight class based on multiple factors.
Determine Freight Class

1. Density: How much weight does the freight have about its size?

The weight of the shipment per cubic foot is considered the most. Higher-density items are usually assigned lower freight classes.

2. Liability: How valuable is the freight?

Does the shipment have highly valuable items that are at risk of theft or damage? High-value items can lead to higher classes.
3. Stowability: How difficult is the freight to handle?
The factors considered are shape, size, stackable, fragility, and hazardous. Easy-to-stow cargo maximizes the use of space on the truck and minimizes the risk of damage. For example, perishable or hazardous items may have higher classes due to their unique storage requirements.

4. Handling: How easy is it to store the freight in a trailer?

If the shipment is difficult to handle, and requires special care or handling such as fragile, hazardous, or oversized boxes might receive higher classes.

How to Calculate your Freight Class

Now that we have understood about what a freight class is and how to determine your NMFC freight class. Let’s ponder more into freight class calculations.
1. Dimension your Shipment:

Foremost, every shipment requires accurate measurement and weight. Using an automated dimensioning system can aid in accurately measuring and weighing your shipment because these data are crucial for freight class calculations. This enables transparent billing and eases the shipping process.

2. Density Calculator:
The density of the shipment is a major factor in determining the freight class of a shipment. Understanding the density is important to correctly categorize your shipment.
The calculation of the density of the shipment is as follows.

Density = Weight of the shipment / Volume of the shipment
Volume of the shipment (cubic feet) = (L * W * H) / 1728.
1 cubic foot = 1728 cubic inches

Example of density calculation:

Consider the package dimensions as Length is 25 inches, Width is 20 inches, Height is 30 inches, and Weight of the shipment is 70 lbs.
Volume of the shipment = (25*20*30) / 1728 = 8.6805 cubic feet.
Density = 70/ 8.6805 = 8.064 lbs per cubic foot.
3. Identify the NMFC Code for your Commodity:
As discussed earlier, The NMFC code is a unique identifier assigned to each commodity shipped through LTL carriers. Based on your shipment density and other factors in determining freight class (liability, stowability, and handling) you should choose the appropriate NMFC code.
Once you have identified the NMFC code, double-check to ensure its accuracy. Errors in classification can lead to incorrect shipping costs and potential disputes during transit.
4. Based on NMFC code, Look up the Freight Class Number:
A freight class number is assigned for each NMFC code. There are 18 distinct freight classes listed for each NMFC code. Picking a wrong freight class for your shipment can lead to additional shipping cost.
Explore the NMFC Freight classification chart below which covers most of the commonly shipped items.
Get your free, downloadable PDF freight class chart now!
Freight Class Chart
Class Commodities Weight per Cubic Foot (lbs) Cost Implications
Durable freight that fits on a standard 4' × 4' pallet
Over 50 lbs
Least Expensive
Bricks, cement, hardwood flooring, construction materials
35 - 50 lbs
Car accessories, car parts
30 - 35 lbs
Car accessories and parts, boxed books, bottled drinks
22.5 - 30 lbs
Car accessories and parts, auto engines, food items
15 - 22.5 lbs
Tires, bathroom fixtures
13.5 - 15 lbs
Crated machinery, cast iron stoves
12 - 13.5 lbs
Computers, monitors, refrigerators
10.5 - 12 lbs
Car covers, canvas, boat covers, wine cases, caskets
9 - 10.5 lbs
Cabinets, framed art, table saws
8 - 9 lbs
Small home appliances
7 - 8 lbs
Auto sheet metal, bookcases
6 - 7 lbs
Clothing, couches, stuffed furniture
5 - 6 lbs
Sheet metal parts, aluminum tables, packaged mattresses, aircraft parts
4 - 5 lbs
Mattresses and box springs, plasma TVs, bamboo furniture
3 - 4 lbs
Model boats, assembled chairs, tables, wood cabinets
2 - 3 lbs
Deer antlers
1 - 2 lbs
Gold dust, ping pong balls
Less than 1 lbs
Most Expensive
For example, an antique vase might be relatively lightweight but highly valuable and fragile, resulting in a higher NMFC class (higher shipping cost). On the other hand, a dense and robust steel beam might have a lower NMFC class (lower shipping cost) due to its high density and low fragility.
Here are some examples of how NMFC codes are mapped to freight class:
Commodity NMFC Code Freight Class
Steel Pipes
Wooden Furniture
If you take a closer look at the table, products like bricks and steel pipes have different NMFC code but fall under the NMFC freight class 55.
A precise freight class ensures fair shipping costs and minimizes surprise surcharges, ultimately streamlining your shipping process.

Frequently Asked Questions

How to dispute a reclassification?

Reclassification of the freight happens when the LTL carrier finds a discrepancy between the freight class on the bill of lading and the actual freight class. To dispute a reclassification
  • Keep the required documents like bill of lading, shipment details, original classifications, etc.
  • Review the NMFC guidelines to ensure that your shipments have been correctly classified.
  • Pay attention to the reason for reclassification. Often reclassification happens when there is a discrepancy between the item shipped and the initial information provided. Make sure to provide the updated information.
  • Discuss and seek help regarding reclassification from your carrier or freight broker.

How does a change in freight class impact the shipping cost?

Consider you have a shipment of durable, car accessories and you have classified the shipment as class 65. However, after revaluation, you figured it out that these parts can be classified as under class 60 because they are denser and stowable.
  • As you move the freight class from 65 to 60, your shipping cost decreases as lower-class shipments are generally less expensive.
  • The reduction in freight class means you’ll pay a lower rate for the same weight, leading to cost savings.
And vice versa is applicable when you move the freight class from lower to high class.

Are freight classes universal?

Freight classes are not universal; rather, they are specific to the National Motor Freight Classification (NMFC) system used in the United States for less-than-truckload (LTL) shipments. However, there are a few exceptions. 1. Some carriers may have their own proprietary freight classification system. 2. Some carriers may offer different freight class discounts based on their shipments like high volume or certain types of commodities.

Which freight class is the cheapest and why?

Freight class 50 is the cheapest because commodities that are assigned to freight class 50 are high in density, have a low value, and have less risk in handling. As a result, carriers can ship these commodities more efficiently and at a lower cost.

What is freight class 60?

Freight class 60 is a relatively low freight class that weighs between 30 to 35 lbs per cubic foot. The goods in this classification are not extremely heavy, but they are denser than those classified under lower classes. Freight class 60 items may have moderate stowability requirements and handling characteristics. They predominantly contain car accessories, car parts, etc.


Understanding the nuances of freight class, you can significantly impact your shipping costs. By now you would have known how to determine freight class, and how to calculate it. This helps you to make more informed decisions, ensuring your shipment reaches its destination efficiently and cost-effectively. Furthermore, it assists in negotiating better rates and plan your logistics efficiently.
Curious about how dimensioning systems can streamline your freight class classification? Chat with our experts for answers!
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