NMFC lookup is a step almost every new LTL shipper runs into — a quote form asks for an NMFC code or freight class, and you're not sure where to find it. This article covers what NMFC is, how it maps to freight class, why reclass and rebilled invoices happen, and how to use ShipMay's free lookup tool.
First, a Quick Clarification: NMFC Isn't NFC or NCM
It's an easy mix-up — NFC is Near Field Communication (the phone tap-to-pay technology), and NCM is Brazil's customs tariff code (Nomenclatura Comum do Mercosul). Neither has anything to do with U.S. freight. NMFC (National Motor Freight Classification), the subject of this article, is the freight classification standard used specifically for U.S. LTL shipping — three similar-looking acronyms, three completely different things.
What Is NMFC, and How Does It Relate to Freight Class?
NMFC is maintained by NMFTA (the National Motor Freight Traffic Association). Every commodity type is assigned an NMFC code, and each code maps to one or more freight classes (ranging from 50 to 500, across 18 tiers). LTL rates are calculated based on freight class — generally, the lower the class, the lower the per-pound rate.
How Freight Class Is Calculated: Density Is the Key Factor
Freight class is based on density — total weight divided by total volume (measured by the shipment's outer dimensions, including the pallet and any packaging that extends past its edge). The denser the shipment, the lower the class tends to be, and the lower the rate. Effective July 19, 2025, NMFTA shifted classification from a commodity-list approach to a density-based scale (expanded from 11 to 13 tiers, adding Class 50 and 55): commodities without handling/stowability/liability concerns now use this density scale, making density the primary factor. Commodities flagged HSL (Handling, Stowability, Liability) still get evaluated on those other three factors as well.
Why Do Reclass and Rebilled Invoices Happen?
The weight, dimensions, and commodity description on a quote are often estimates, not actual measurements. Once freight reaches a carrier terminal, most major carriers run automated measurement equipment on a sample of shipments — if the actual density doesn't match what was quoted, the carrier may reclassify the shipment to a different class, or adjust the weight (reweigh), and the invoice changes accordingly. For how to gather evidence and verify your invoice, see LTL Reweigh and Reclass: Why Freight Bills Change After Pickup; for the full accessorial charge list, see Freight Accessorial Charges Explained.
How to Use ShipMay's NMFC Lookup Tool
Not sure which NMFC code or freight class your shipment falls under? Use ShipMay's free NMFC lookup tool — enter the commodity description and get the matching code and reference class, without digging through a tariff manual yourself. If your shipment falls into electronics, furniture/glass, food/packaging, building materials/metal, or auto parts, check the matching category guide: Electronics, Furniture and Glassware, Food and Packaging, Building Materials and Metal, Auto Parts.
How ShipMay Helps
Still not sure how to quote after looking up your code? Tell ShipMay the commodity, weight, and dimensions, and get a quote — we'll help confirm the class matches your rate.
Related Reading
- LTL Reweigh and Reclass: Why Freight Bills Change After Pickup
- Freight Accessorial Charges Explained
- How Are U.S. Trucking Freight Costs Calculated?
- LTL, Partial, or FTL: Choosing by Weight and Pallet Count
- Free NMFC Lookup Tool
- Logistics Tools
Reference
- National Motor Freight Traffic Association (NMFTA), which maintains the NMFC classification standard and freight class system.
