Freight Classes and the 2025 NMFC Changes

Anyone shipping less-than-truckload (LTL) freight in the United States runs into freight classes sooner or later. The class assigned to a shipment is one of the main inputs to an LTL price, and a class that turns out to be wrong can mean a corrected bill after delivery. The system behind those classes changed significantly in 2025, when density became the deciding factor for many more commodities. This guide explains how classification works now and what shippers can do to get it right.

What the NMFC is

The National Motor Freight Classification (NMFC) is maintained by the National Motor Freight Traffic Association (NMFTA). It assigns each commodity a freight class from 50 to 500 based on four transportation characteristics: density, handling, stowability and liability. In NMFTA's words, the denser and easier freight is to move, the lower the class and the lower the cost.

NMFTA gives bricks, cement and billets as examples of dense, easy-to-handle class 50 freight. At the other end, class 500 covers items that are light, bulky, fragile or hazardous, such as ping pong balls, feathers or explosives, according to an NMFTA guide for shippers.

The four characteristics work like this:

Density: how heavy the freight is relative to the space it takes up, in pounds per cubic foot (pcf).
Handling: whether size, weight, shape, fragility or hazards make the freight harder to move across a dock.
Stowability: how well it fits with other freight, for example whether it can be stacked or has protrusions.
Liability: how likely the freight is to be damaged, damage other freight or spoil, and whether it is hazardous.

NMFTA describes the NMFC as a voluntary standard, so carriers and shippers can agree on other pricing, such as freight all kinds (FAK) rates. Even under an FAK agreement, NMFTA notes that a carrier may reclass an item that is significantly different from what was represented and apply additional charges.

What changed in 2025

NMFTA amends the NMFC through a public process run by its Freight Classification Development Council (FCDC). Proposals are published in a docket, the council's decisions are announced in a disposition bulletin and the approved changes take effect through a supplement to the classification.

The 2025 overhaul came through Docket 2025-1. NMFTA's Disposition Bulletin 1371 states that the supplement carrying the changes was scheduled to be issued on May 10, 2025, "with an effective date of July 19, 2025." The main changes were:

A standard 13-step density scale. The FCDC's 11-subprovision density scale was expanded to 13 subprovisions, adding breaks that put the densest freight in classes 55 and 50.
Fewer, broader listings. NMFC items grouped under generic headings with no known handling, stowability or liability concerns were canceled and referenced within a single 13-sub density item for that heading. NMFTA said their commodity descriptions and minimum packaging requirements would be kept in the new item.
Exceptions for special freight. Items with identified handling, stowability or liability characteristics are classed on those characteristics and may have density breaks that do not follow the standard scale.

The standard scale adopted in Docket 2025-1 is shown below. It applies only to items that reference it, so the actual NMFC item for a product always controls.

Density (pounds per cubic foot)	Class
Less than 1	400
1 but less than 2	300
2 but less than 4	250
4 but less than 6	175
6 but less than 8	125
8 but less than 10	100
10 but less than 12	92.5
12 but less than 15	85
15 but less than 22.5	70
22.5 but less than 30	65
30 but less than 35	60
35 but less than 50	55
50 or greater	50

How to calculate density

NMFTA's FAQ on the 2025 changes sets out the method for a handling unit, such as a pallet or crate:

Measure the greatest length, width and height in inches, including any projections, as the unit is tendered to the carrier.
Multiply the three dimensions and divide by 1,728 to convert cubic inches to cubic feet.
Divide the unit's weight in pounds by its cubic feet. The result is density in pcf.

NMFTA's own example is a pallet of boxes measuring 48 by 40 by 45 inches and weighing 450 pounds. That is 86,400 cubic inches, or 50 cubic feet, for a density of 9 pcf. If the commodity uses the standard 13-sub scale, 9 pcf falls in the 8 to 10 pcf band, which is class 100.

For shipments with several handling units, the FAQ quotes NMFC Item 110: density is calculated on each handling unit, except that when the shipping papers show only a total weight, total weight and total cube may be used.

The NMFC keeps changing

NMFTA described the July 2025 update as only Phase 1 of a larger overhaul, and amendments have continued. Docket 2025-2 had an effective date of December 6, 2025, according to its disposition bulletin. Docket 2026-2, issued August 28, 2026, proposes further changes, with any approved amendments scheduled to take effect on December 12, 2026. A class looked up a year ago may no longer be current.

Reweighs, reclasses and disputes

If the weight, dimensions or description on the bill of lading do not match the freight, a carrier can reweigh or remeasure it, apply the correct class and bill the difference. NMFTA warns that a wrong classification "can trigger additional freight charges, audit disputes, or unnecessary claims," and lists reweighs and rebills among the usual consequences. Some carriers' rules tariffs also include a separate charge for inspecting, reweighing or reclassifying a shipment, so it is worth reading the tariff before shipping.

Shippers have rights in this process. Under 49 U.S.C. 13710, a motor carrier of property must provide, on request, a copy of the rate, classification, rules and practices behind its charges. The same section requires a carrier to issue any bill for additional charges within 180 days of the receipt of the original bill, and a shipper that wants to contest a bill must do so within 180 days of receiving it.

What shippers should do

Confirm the NMFC item for each product. NMFTA's ClassIT+ service and its interpretations team can help identify the correct item, especially after a consolidation.
Measure freight as tendered. Include the pallet, packaging and any overhang, because the carrier will measure the greatest dimensions.
Weigh on a scale. Use actual shipping weights rather than estimates from product specifications.
Record dimensions on the bill of lading. NMFTA recommends recording exact dimensions on every bill of lading, packing freight compactly and training staff to calculate density.
Review packaging. NMFC items can set minimum packaging requirements, and a more compact package can raise density and lower the class.
Update systems and agreements. NMFTA advised shippers to audit bill of lading and transportation management system data, and FAK terms are worth reviewing with each carrier.
Keep records. Photos, scale tickets and measurement notes make it easier to question a reweigh or reclass.

This guide is general information about shipping freight by truck. It is not legal advice, and rules can change, so check the official sources above for your situation. TNW Trucking is an independent freight information resource. It is not a motor carrier or freight broker and is not affiliated with any trucking company of a similar name.

Freight classes explained: the NMFC, density and the changes that took effect in 2025