What Is Freight Class?

Who decides freight class

Freight classes come from the National Motor Freight Classification, or NMFC, a catalogue maintained by the National Motor Freight Traffic Association. Nearly every LTL carrier in the United States prices against it. The NMFC lists commodities and assigns each an item number and a class, so that a carrier in Ohio and a carrier in Nevada rate the same pallet of goods the same way.

The system exists because LTL trailers are shared. When five customers’ freight travels in one truck, the carrier needs a fair way to decide what share of the cost each shipment carries. Weight alone does not work — a pallet of feathers and a pallet of steel weigh very differently, but a light, bulky pallet can consume more trailer space than a heavy compact one. Classification solves that.

The four factors

Four characteristics determine a commodity’s class.

Density is weight relative to the space occupied, measured in pounds per cubic foot. It is the dominant factor and, for a large and growing share of commodities, the only one that matters. Dense freight earns a low class and a low rate.

Stowability is how well the freight loads alongside other freight. Items that are oddly shaped, excessively long, hazardous, or that cannot be stacked take up space that cannot be sold to anyone else, and are rated higher as a result.

Handling is the effort required to load and unload. Most freight moves by forklift without incident. Freight that is fragile, unpackaged, awkwardly balanced or that requires special equipment costs the carrier more in labor and time.

Liability is the risk the carrier absorbs. High-value goods, perishables, and anything prone to theft or to damaging surrounding freight carry more risk, and therefore a higher class.

How density is calculated

Density is straightforward arithmetic. Multiply length by width by height in inches to get total cubic inches, then divide by 1,728 to convert to cubic feet. Divide the shipment’s total weight in pounds by that cubic footage, and the result is density in pounds per cubic foot.

A pallet measuring 48 by 40 by 48 inches occupies 92,160 cubic inches, or 53.3 cubic feet. If it weighs 700 pounds, its density is 13.1 pounds per cubic foot, placing it in class 85. Our freight class calculator does this for you and returns the class directly.

One detail catches people out constantly: measure the outside of the packaging, and include the pallet. Carriers measure what they physically load. A 42-inch stack on a 6-inch pallet is a 48-inch shipment, and using 42 will produce a density figure that does not match what the carrier records.

What the 2025 restructuring changed

The NMFC underwent the most significant overhaul in nearly ninety years in 2025. Docket 2025-1 took effect on 19 July 2025, consolidated roughly 2,000 commodity listings, and moved a large number of items onto density-based classification.

It also changed the density scale itself. The scale expanded from eleven subprovisions to thirteen: the old top band of “30 or greater” was split, and two new bands were added above it — 35 up to 50 pounds per cubic foot at class 55, and 50 or greater at class 50. Classes 50 and 55 had not previously been reachable through density at all, so very dense freight can now rate lower, and more cheaply, than it could before.

This is worth knowing because most freight calculators and reference charts online still publish an older 18-row table that maps every class to a density band. The density provision does not work that way: it assigns thirteen classes, and five of the eighteen — 77.5, 110, 150, 200 and 500 — are never produced by density. The two versions agree at and above 15 pounds per cubic foot and diverge below it. The full freight class chart shows both side by side.

If you are working from a classification you established some years ago, verify it against the current publication before assuming it still applies.

Why the class matters to your invoice

LTL rates are quoted per hundredweight against a class. The lower the class, the lower the rate. Moving a shipment from class 175 down to class 100 can change the cost substantially — often by a third or more on the same lane.

This creates an obvious temptation to enter a lower class, and an equally obvious reason carriers guard against it. Most terminals run dimensioning and weighing equipment that captures every pallet passing through. When the recorded figures do not match the bill of lading, the shipment is reclassified, the invoice is corrected, and an inspection or reclassification fee is usually added. Underclassing does not reduce cost; it defers and increases it.

Getting it right

Start by calculating density accurately, using real measured dimensions and the actual gross weight including packaging and pallet. Check whether your commodity has a fixed NMFC listing rather than a density-based one — many do, and for those the listed class governs regardless of what the density works out to. The NMFC code lookup shows which common commodities rate on density and which carry a fixed class. Keep a record of your classifications so repeat shipments are consistent. And if a commodity sits near a bracket boundary, confirm with your carrier before booking rather than after.

When you have your dimensions to hand, the freight class calculator will give you the density, the cubic footage and the class in one step.

Freight class and parcel shipping

Freight class applies to LTL pallet freight, not to parcel carriers. UPS, FedEx Ground and USPS use dimensional weight instead — a related idea, in that both price bulky lightweight goods by the space they occupy, but a different calculation. If you are shipping boxes rather than pallets, use the dimensional weight calculator.

Full truckload freight does not use classification either. When you buy the whole trailer, pricing is negotiated by lane and the fairness problem classification solves does not arise.

Figures are indicative. Confirm classification with your carrier before booking.