Freight class drives your LTL price. Here is how classes are assigned—and how to avoid costly reclassifications.
The National Motor Freight Classification (NMFC) system sorts LTL freight into 18 classes, from 50 to 500. Your class is one of the biggest levers on your rate—so understanding it is money in your pocket. Lower classes generally cost less to ship; higher classes cost more.
The four factors
Classification is not arbitrary. Every commodity is evaluated on four characteristics that together describe how easy or hard it is to transport.
- Density—weight relative to the space the freight occupies.
- Stowability—how easily it loads and travels alongside other freight.
- Handling—the care and effort required to move it safely.
- Liability—value, fragility and risk of damage or theft.
Density does most of the work
For most commodities, density is the dominant factor. Higher density usually means a lower class and a lower rate, because dense freight uses trailer space efficiently. To calculate density, divide the weight of your shipment by its total cubic feet—including the pallet and any overhang. Measuring your fully packaged dimensions accurately is the single best way to protect your pricing.
Density-based classes
Many commodities now fall under density-based NMFC items, where the class shifts automatically with the density you provide. That makes accurate measurement even more important—a small error in dimensions can bump you into a higher class and a bigger bill.
Avoiding reclassifications
Carriers re-weigh and re-measure at the terminal. If your paperwork does not match the freight, expect a reclassification and an adjusted invoice—often weeks after delivery, when it is hardest to dispute. Get the class right up front, keep your dimension and weight records, and those surprises disappear.
When in doubt, ask. A quick check on a new commodity is far cheaper than a reclassification, and our team can verify the right class before you ever book. Accuracy is not just about compliance—it is the most reliable way to keep your LTL costs exactly where you expect them.
Written by
Lisa T.
