Freight Class (NMFC): Freight Class
An 18-tier density-based classification (Class 50–500) that determines LTL pricing under the NMFC.
Freight class is a standardized classification under the National Motor Freight Classification (NMFC) system that LTL carriers use to price shipments. Class is driven primarily by density — pounds per cubic foot — along with handling, stowability, and liability. Denser, easier-to-handle freight (Class 50) is the cheapest to ship; light, bulky, or fragile freight (Class 500) is the most expensive.
Who publishes it
National Motor Freight Traffic Association (NMFTA), which maintains the NMFC.
How to read it
- Density = weight (lbs) ÷ cubic feet, where cubic feet = (L × W × H in inches) ÷ 1728.
- Roughly: 50+ lbs/ft³ → Class 50 (cheapest); under 1 lb/ft³ → Class 500 (most expensive).
- A July 2025 NMFC update moved the system to a density-first framework, replacing much of the older commodity-code-driven classification.
- Misclassifying freight — intentionally or not — is one of the most common causes of reweigh/reclass fees after pickup.
Why it matters
Getting freight class wrong is the single most common source of LTL billing disputes. A shipper who under-declares class to get a lower quote will usually eat a reclass fee once the carrier inspects and reweighs the shipment — often larger than the savings would have been.
Frequently asked questions
How do I calculate my freight class?
Calculate density first: divide the shipment's weight in pounds by its cubic feet (length × width × height in inches, divided by 1728). Match that density figure to the NMFC density-to-class table to get your class.
What happens if I use the wrong freight class on a BOL?
Carriers routinely inspect and reweigh LTL freight. If the actual class is higher than what's declared on the Bill of Lading, you'll be billed a reclassification fee for the difference — plus the original quote is no longer valid.
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