How To Determine Class For LTL Freight:
Understanding how to determine the freight class for LTL (Less Than Truckload) shipments is essential for accurate pricing, proper documentation, and efficient transportation. This guide explains everything you need to know about freight classification, from NMFC codes to density-based calculations, so you can ship smarter, avoid reclassification fees, and control your costs.
What is Freight Class?
Freight class is a standardized system developed by the National Motor Freight Traffic Association (NMFTA) to organize cargo into 18 categories, ranging from Class 50 to Class 500. Each class helps carriers and shippers determine accurate shipping rates based on density, stowability, handling, and liability.
Lower classes (e.g., 50) = Represent dense, durable, and easy-to-handle shipments that cost less to move.
Higher classes (e.g., 500) = ndicate lightweight, fragile, or awkwardly shaped freight that costs more to transport.
Think of it like golf: there are 18 “holes” (or classes), and the goal is to keep your score, or freight class, as low as possible to minimize shipping costs.
Example: Steel Bolts vs. Ping-Pong Balls
Steel bolts are dense, compact, and durable, which earns them a Class 50 rating—the lowest and cheapest.
Ping-pong balls, on the other hand, are lightweight, bulky for their weight, and fragile. They fall into Class 500, the highest and most expensive.
This contrast shows why freight class matters. Two items on the same truck can cost drastically different amounts to ship.
The National Motor Freight Classification system aka “NMFC” is a grading system for the thousands of freight commodities that move by truck in the US. There are 18 classifications (from 50-500). The classifications are based on the 4 characteristics of ship-ability (density, handling, stowability and liability). The more shippable your freight is the lower the class (50 is lowest and cheapest). It’s a lot like golf: There are 18 holes (or classifications) and you want to have the lowest score (or class) possible to avoid paying more.
4 Factors in Determining Freight Shipping Class
Freight class is a standardized classification that helps the shipping industry determine accurate freight costs. The National Motor Freight Traffic Association’s (NMFTA) system uses four main factors to classify LTL shipments. Understanding these ensures you can determine the correct freight class and avoid unexpected charges.
1. Density
Density is the most important factor in determining freight class. It measures how heavy your shipment is compared to the space it occupies, expressed in pounds per cubic foot (lb/ft³).
Density Formula:
Density = Weight (lbs) ÷ (Length × Width × Height ÷ 1,728)
(There are 1,728 cubic inches in one cubic foot.)
Example:
If your shipment weighs 600 lbs and measures 48 in × 40 in × 36 in,
then:
Density=(48×40×36)/1728600=13.5lb/ft³
Higher density (more pounds per cubic foot) means a lower freight class and lower cost, while lower density leads to a higher class and higher cost.
2. Stowability
Stowability reflects how easily your shipment can be stored or transported with other freight. Cargo that is oddly shaped, oversized, or hazardous can be difficult to stack or secure and is therefore assigned a higher freight class.
Standard, stackable freight that makes efficient use of space typically qualifies for lower classes and reduced rates.
3. Handling
Handling considers how easy or difficult your freight is to load, move, and unload. Shipments that require extra care, special equipment, or multiple touchpoints during transit are given higher class ratings. Improving packaging, such as securing items on pallets or in crates, can make handling easier and reduce your freight class.
4. Liability
Liability measures the risk of damage, loss, or theft during transit. Fragile, perishable, or high-value shipments are rated with higher classes due to increased risk exposure.
Accurately classifying freight based on liability ensures compliance with NMFTA standards and helps avoid carrier disputes or insurance complications.
Steps to Determine LTL Freight Class
Determining your LTL freight class correctly ensures accurate pricing, smooth carrier handling, and compliance with NMFTA standards. Follow these key steps to classify your shipment properly and avoid costly reclassification fees.
1. Have a basic description of what you are shipping.
Start by identifying what materials make up your shipment, such as steel, wood, plastic, or fabric. This information helps define your freight’s density, stowability, and liability.
Example:
If you’re shipping steel bolts, they are dense, compact, and nearly indestructible. This gives them a Class 50 rating, one of the lowest and most affordable in the NMFC system.
2. Determine how your shipment is packaged.
Packaging type directly influences your freight class because it affects how easily your shipment can be stored and handled.
Common packaging types include pallets, skids, crates, drums, and carboys. Proper packaging helps improve safety and reduces the risk of damage or reclassification.
Example:
If you’re shipping temperature-sensitive or fragile materials, like biological samples or chemicals, they’ll require insulated containers or self-contained refrigerants. These factors increase handling complexity and risk, raising the freight class, sometimes up to Class 500 for high-liability items.
3. Use the Freight Class Chart.
Refer to the freight class chart to find the appropriate class for your shipment based on its density. Here’s a brief overview:
Higher freight classes typically result in higher shipping costs, while lower classes can save you money.
4. Determine if your shipment is hazardous.
If your freight includes hazardous or perishable materials, such as food, chemicals, or biological samples, it must be properly packaged, labeled, and declared according to FMCSA and NMFTA regulations. Read more about food transportation best practices to see how temperature control affects classification and handling.
Information on packaging, marking, and declaration of hazardous materials can be found on the FMCSA website.
Example:
Shipping something hazardous, such as industrial chemicals or batteries, requires the shipper and carrier to ensure full compliance for safe transit. Every hazardous shipment must be:
Noted on the Bill of Lading (BOL)
Tagged and labeled on all containers
Placarded on all trucks during transport
Keep in mind that hazardous freight often can’t be shipped with food or other incompatible materials.
A reputable freight broker can help verify compliance, ensure documentation accuracy, and often negotiate or waive hazmat surcharges.
5. Weigh your shipment.
Having an accurate shipment weight is critical because it directly affects your freight rate and, in many cases, your freight class. For density-rated items, even small inaccuracies in weight can alter your shipment’s density and therefore its class and cost.
6. Measure your shipment.
Use a tape measure or dimensioning device to record the shipment’s length, width, and height. Carriers use these dimensions to calculate cubic footage and density. Always measure from the outermost edges, including packaging.
Density=Length (in)×Width (in)×Height (in)/1728Weight (lbs)
Example:
A shipment of ping-pong balls takes up a large amount of space but weighs very little, making it a Class 500 freight item. In contrast, dense metal parts occupy less space but weigh more, qualifying for a lower class and lower cost.
Carriers charge for the space your freight occupies. If a shipment has an unusual shape (like a swing set with an 8-foot pole), that dimension counts toward the total height. This can trigger “excessive length” or “density minimum rule” charges.
However, experienced brokers can often negotiate these accessorial fees or have them reduced.
7. Contact your freight broker.
If you’re uncertain about your NMFC item number or class, contact your freight broker or carrier representative. They can verify your item code, confirm proper classification, and prevent billing surprises.
Brokers typically have NMFC database access, saving you from expensive subscriptions and the risk of misclassification.
For best results:
Follow the above steps carefully to understand how your freight class is determined.
Once you’ve mastered the process, you’ll be able to identify your class quickly and accurately.
For additional insights, explore 6 Reasons Small Businesses & Startups Should Use a Freight Broker, an essential resource for shippers aiming to save time and money.
For the purposes of getting your freight class I would recommend following the steps above once (thoroughly) to learn how the class is determined. Once you understand the process you should have most of the information you need to do everything else on the fly. Spend the extra time reading about the 6 Reasons small businesses & startups should use a freight broker.
Freight Class FAQ
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The NMFC code is a unique identifier assigned to each freight classification, which helps streamline the LTL freight shipping process.
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Higher freight classes often lead to increased shipping costs due to the greater liability and handling requirements associated with those items.
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No, the freight class is determined before shipping, and changes after shipment can lead to additional charges or delays.
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Items that are fragile, lightweight, or require special handling, such as glassware or high-value electronics, are typically assigned higher freight classes.
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No, each freight class has a specific density range, which is crucial for determining the correct classification.
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If you assign the wrong class, the carrier may reweigh and reclassify your shipment, which can result in extra fees, delivery delays, or billing disputes. Always verify your shipment’s density and NMFC code before booking.
Contact TFWWI for Accurate Freight Classification
Getting your freight class right is essential for saving on LTL shipments. Contact TFWWI today to classify your freight correctly and optimize your LTL freight shipping process!