Freight class and density: how to classify a pallet shipment

Freight class is the rating LTL carriers in the United States use to price a shipment. It comes from the National Motor Freight Classification (NMFC), published by the National Motor Freight Traffic Association (NMFTA). For most palletized freight today, class depends mainly on density: how many pounds the shipment weighs per cubic foot of space it takes. This guide shows how to calculate density, gives the current density scale, and explains how pallet choices change the result.

#What freight class means

Freight class groups commodities by how costly they are to carry. The NMFC uses 18 classes, from 50 (dense, easy to handle) to 500 (light, bulky or fragile). A higher class means a higher rate per hundredweight on the same lane.

Four characteristics determine a commodity's class in the NMFC: density, stowability, handling and liability. Density is the dominant factor for most freight, and in 2025 the NMFC moved many more items to density-based classes.

The 18 classes are:

Freight class applies to LTL. Full truckloads are normally priced per trip or per mile, and weight and trailer space matter instead of class. See pallets per truckload.

#How to calculate freight density

1. Measure the loaded pallet at its longest, widest and tallest points, including the pallet, overhang and wrap. Many carriers round each dimension up to the next inch.
2. Cubic feet = L × W × H (inches) ÷ 1,728.
3. Weigh the whole unit, including the pallet.
4. Density = weight (lb) ÷ cubic feet.

For metric: m³ = L × W × H (mm) ÷ 1,000,000,000, and 1 lb/ft³ = 16.02 kg/m³.

#The NMFC 13-tier density scale (effective July 19, 2025)

NMFTA's Docket 2025-1 took effect on July 19, 2025. It moved many commodities from commodity-based classes to density-based classes, consolidated a large number of NMFC items, and replaced the previous 11-tier density scale with a 13-tier scale.

The scale is shown as published by NMFTA and reproduced by carriers. Not every NMFC item uses it: some commodities keep a specific class, and the item's own rules decide. Always look up the NMFC item for your product, or ask your carrier. NMFTA continues to issue dockets that change classifications, so check for updates before relying on an older class.

#Worked examples on a 48 × 40 pallet

These assume the commodity's NMFC item uses the full density scale.

#How pallet choices change freight class

The pallet is part of the shipment, so it affects both sides of the density calculation.

#Height

A 48 × 40 pallet adds about 4-3/4 to 6 in to the load height. On a 48 × 40 × 48 in load of 1,000 lb, a 6 in pallet is 12.5% of the height. A lower pallet, or fitting more product per layer to reduce layers, raises density. See pallet height.

#Overhang

Carriers measure the outside dimensions. A 48 × 40 load that overhangs 2 in on every side measures 52 × 44 in, 19% more floor area at the same weight. That can push a load across a class break. See pallet overhang.

#Footprint

A pallet larger than the load adds volume with no product. Sizing the pallet to the load footprint keeps the billed cube down. For example, a 40 × 40 in load shipped on a 48 × 40 pallet is billed as 48 × 40, 20% more floor area than the product needs. If the load is always that size, a 40 × 40 pallet raises density and usually costs less to buy as well.

#Weight

The pallet's own weight is included, which slightly increases density. A heavy pallet does not save money, though: you pay for the weight too. See pallet weight.

#Stackability

A load that cannot be stacked may attract space-based charges on top of its class. Flat, strong tops help. See shipping pallets LTL.

#Example: finding a class break

A shipper sends 700 lb of product on a 48 × 40 pallet. Loaded height is 52 in.

• Volume: 48 × 40 × 52 ÷ 1,728 = 57.8 ft³
• Density: 700 ÷ 57.8 = 12.1 lb/ft³ (class 85)

If the load were built 4 in taller, at 56 in:

• Volume: 62.2 ft³
• Density: 11.25 lb/ft³ (class 92.5)

Four inches of height moved the shipment up one class. Checking the class breaks before choosing a pattern and pallet height is one of the cheapest ways to reduce LTL cost.

#Density-based and commodity-based items

Each NMFC item says how its class is set:

• Density-based items use a density scale, now usually the 13-tier scale above. Your class changes with how you pack and palletize.
• Commodity-based items have a fixed class, sometimes with separate classes for different packaging. Palletizing better does not change the class, though it still affects damage and stackability.
• Items with special provisions may have minimum densities, packaging requirements or different classes for assembled and knocked-down goods.

The NMFC item description, not the product's common name, decides which applies. Two products that look similar can fall under different items.

#Common mistakes

• Using the product's dimensions instead of the loaded pallet's.
• Leaving out the pallet weight or height.
• Guessing the class from an old bill of lading after an NMFC change.
• Wrong NMFC item. Similar products can be in different items with different rules.
• Measuring before wrapping. Film and corner boards add size.

A carrier that finds different dimensions, weight or class will reclass or reweigh the shipment and bill the difference, often with a fee.

#Handling unit rules

NMFC rules and carrier tariffs define how density is applied when a shipment has several pallets of different densities, and NMFTA has considered further changes to how individual handling units are classified. Treat each pallet's density as something to know, not just the shipment total, and check the current rules with your carrier.

#Designing pallets with freight in mind

If you ship LTL often, include the load height and footprint in the pallet spec and design the pallet and pattern together. A custom pallet that matches the load footprint, with a low profile, can move a shipment into a lower class. Start with the 48 × 40 template, or read unit load design.