NMFC Code (National Motor Freight Classification)

The National Motor Freight Classification (NMFC) is a standardized system used almost exclusively in LTL (less-than-truckload) trucking to price and handle freight. It sorts every commodity into one of 18 freight classes, numbered 50 to 500, based on four characteristics: density, stowability, handling, and liability. Density — weight per cubic foot — is the dominant factor; NMFTA moved most commodities onto a density-based scale so that class is calculated directly from an item's dimensions and weight rather than looked up by description alone. Stowability accounts for items that are awkward to load with other freight (unusually long, heavy, or hazardous). Handling covers whether a shipment needs special equipment or care. Liability reflects the commodity's susceptibility to damage, theft, or spoilage, and the risk it poses to other freight.

Class	Density (lb/ft³, approx.)	Typical goods
50	over 50	Steel coils, machinery, concrete blocks
55–65	22.5–50	Bricks, hardware, bottled beverages
70–92.5	12–22.5	Auto parts, food items, packaged goods
100–125	6–12	Machinery, small appliances
150–200	4–6	Auto sheet metal, mixed cartons
250–300	1–4	Bulky furniture, wood cabinets
400–500	under 1	Ping pong balls, gold dust, empty bulky containers

Lower classes cost less to ship because they're dense and easy to handle; higher classes cost more because they take up trailer space relative to their weight or require extra care.

An NMFC code (also called an item number) and a freight class are related but different attributes. The NMFC code identifies the specific commodity — for example, a particular category of "furniture, wood, unassembled" — within the National Motor Freight Classification tariff published by NMFTA. Freight class is the pricing tier (50–500) that a given code resolves to. A single NMFC item number can carry several sub-numbers, each tied to a density range or packaging condition (loose, palletized, crated), and each sub-number can point to a different freight class. So two shipments of visually similar product can carry the same NMFC code but different freight classes if their densities differ, or different NMFC codes entirely if one has added liability risk (fragility, high value, hazmat).

In practice: freight class answers "what does this cost to ship," while the NMFC code answers "what is this, specifically, for classification purposes." Carriers and rating systems need both to quote and bill correctly.

The NMFC code and freight class appear on the bill of lading (BOL) for every LTL shipment and drive the rate a carrier quotes. Because LTL trailers carry many customers' freight at once, carriers price by a combination of weight, distance, and how much trailer space and handling a shipment actually consumes — which is exactly what class is designed to capture. Full truckload (FTL) shipments, where one customer pays for the whole trailer, and small-parcel shipments (handled by parcel carriers like UPS or FedEx Ground) generally don't use NMFC classification at all.

When the class declared on a BOL doesn't match what a carrier's inspection finds — wrong density calculation, wrong commodity description, or a code that understates liability — the carrier reclassifies the shipment and rebills the difference, sometimes well after delivery. This is one of the more common and avoidable cost overruns in LTL freight, and it traces directly back to inaccurate or incomplete product data at the time of shipment.

NMFC code and freight class are product attributes, not just logistics inputs. Any distributor or manufacturer that ships LTL needs accurate class data attached at the SKU level to quote freight correctly — whether that's a freight calculator at checkout, a rate shopping tool, or a TMS/ERP integration pulling class by item. The trouble is that this attribute is frequently missing, outdated, or copied forward incorrectly in supplier-provided product data: a class assigned to one packaging configuration gets applied to a repackaged or resized version of the product, or the field is simply left blank and defaulted to a guess.

That gap is functionally the same problem as a missing HS code or an unmeasured UOM — a required attribute that has to be derived from dimensional, weight, and material data rather than assumed. Anglera's enrichment work covers this kind of attribute: extracting or calculating the dimensional and density data needed to support an accurate freight class and flagging low-confidence values for review, rather than letting stale or blank classification data ride through to a shipment and trigger a reclassification fee.