In less-than-truckload (LTL) shipping, two shipments with the same weight can cost very different amounts to move. One of the biggest reasons is freight class. Getting the classification right keeps quotes accurate and invoices predictable. Getting it wrong often leads to reclassification charges, billing disputes, and delays.
Freight class is a standardized category that LTL carriers use to price shipments based on how easy or difficult the freight is to transport. In the United States, freight classes are defined through the National Motor Freight Classification (NMFC), maintained by the National Motor Freight Traffic Association (NMFTA).
There are 18 freight classes, ranging from class 50 to class 500. Lower classes generally represent dense, durable, easy-to-handle freight and typically cost less to ship. Higher classes generally represent light, bulky, fragile, or difficult freight and typically cost more.
Classification is generally based on four transportation characteristics:
An NMFC code describes what the freight is. The freight class determines how it is priced.
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An NMFC code, sometimes called an NMFC item number, identifies a specific commodity or group of commodities in the National Motor Freight Classification. Each item describes the product and assigns it a freight class, or a set of classes based on density or packaging.
For example, an item may assign one class to freight shipped in boxes and another to the same product shipped loose, or it may assign different classes depending on how many pounds per cubic foot the shipment weighs.
Shippers commonly list the NMFC item number and freight class on the bill of lading so the carrier can rate and handle the shipment correctly.
| Term | What It Means |
|---|---|
| NMFC code | Identifies the commodity and how it is described in the National Motor Freight Classification. |
| Freight class | The pricing category (50 through 500) assigned to that commodity based on its transportation characteristics. |
| Density | Weight per cubic foot, which often determines the class for density-based items. |
| Bill of lading | The shipping document where the commodity description, NMFC item, and class are recorded. |
Density is one of the most important factors in classification. Many NMFC items now assign class based on the shipment's pounds per cubic foot, so accurate measurement matters.
In 2025, NMFTA implemented significant classification changes that moved many commodities to density-based classification and updated how handling units are measured. Shippers who have not reviewed their classifications since those changes should confirm that the NMFC items and classes they use are still current.
The result is pounds per cubic foot. For example, a pallet measuring 48 x 40 x 50 inches and weighing 800 pounds occupies about 55.6 cubic feet, for a density of roughly 14.4 pounds per cubic foot.
Because density depends on the outer dimensions of the handling unit, loosely built pallets or freight that overhangs the pallet can lower density and push a shipment into a higher, more expensive class.
LTL carriers inspect, measure, and weigh freight throughout their networks. When the information on the bill of lading does not match the freight, carriers may correct it.
If a carrier determines that freight belongs in a different class, it may rebill the shipment at the correct class and add an inspection or reclassification fee.
If actual weight or dimensions differ from what was declared, the shipment may be rerated based on the carrier's measurements.
Corrections create invoice variances that must be researched and approved, consuming time from logistics and accounting teams.
When quotes are built on incorrect classes, product pricing, freight budgets, and customer quotes are all built on the wrong numbers.
BTX coordinates domestic, international, and specialized shipments with attention to accurate documentation from pickup through delivery.
Use an accurate description of what the product actually is, not just a general category. The NMFC item description should match the commodity being shipped.
Use calibrated scales and measure the full outer dimensions of each pallet or package. Do not rely on estimates or product catalog dimensions alone.
For density-based items, calculate pounds per cubic foot and apply the class that corresponds to that density.
Stack freight squarely within the pallet footprint and avoid unnecessary overhang. A compact handling unit can improve density and reduce damage.
Record the commodity description, NMFC item number, class, piece count, and weight clearly and consistently.
Products, packaging, and NMFC rules change. Review classifications for frequently shipped items on a regular schedule rather than reusing old values indefinitely.
On the last point, a freight-all-kinds agreement may let multiple classes be rated at a single class for pricing purposes, but the commodity still needs to be described and documented accurately, and FAK terms usually apply only within defined class ranges.
Freight class directly affects what LTL shipments cost. When classifications are based on accurate descriptions, real measurements, and current NMFC items, quotes become more reliable and reclassification charges become less common.
The most effective approach is a consistent process: identify the commodity correctly, measure every handling unit, calculate density when required, and document it clearly on every shipment.
There are 18 freight classes in the National Motor Freight Classification, ranging from class 50 to class 500.
Generally, yes. Lower classes typically represent denser, easier-to-handle freight and usually carry lower rates, while higher classes typically cost more.
NMFC items are published by the National Motor Freight Traffic Association. Shippers are responsible for identifying the item that accurately describes their freight.
The carrier may inspect the shipment, reclassify it, rebill it at the correct class, and add an inspection or reclassification fee.
Multiply length, width, and height in inches, divide by 1,728 to get cubic feet, then divide the weight in pounds by the cubic feet.
Freight class is primarily used for LTL pricing. Full truckload shipments are typically priced by lane, distance, equipment, and market conditions rather than by class.
BTX Global Logistics helps shippers move freight with accurate documentation, flexible transportation options, and proactive communication.