How Freight Class Is Determined: Density Walkthrough

What changed in 2025 and why density now rules

Historically, the National Motor Freight Classification (NMFC) assigned classes by commodity: thousands of item listings, each with its own class based on density, handling, stowability, and liability. In 2025 the NMFTA overhauled this, moving a large share of commodity listings to straight density-based classification on an expanded 13-tier density scale, and consolidating thousands of items in the process.

The practical effect: for most general freight without special handling, stowability, or liability issues, your class is now simply a function of your shipment's density. The old habit of shipping everything at a remembered class ('our stuff is always class 70') is exactly how reclassification fees happen now — the same product on a different pallet configuration can land in a different class.

Some commodities still carry specific NMFC item numbers with their own rules, and freight with unusual handling or liability characteristics can be classed differently regardless of density. When in doubt, look up your NMFC item or ask your carrier — but for typical palletized freight, density is the game.

The density calculation, step by step

Density is total weight divided by total cubic feet. The only trap is measuring honestly — carriers measure with dimensioners at the terminal, and their numbers win disputes unless yours are documented.

1. Measure the true footprint and height in inches, at the widest points — including the pallet, overhang, packaging, and anything sticking out. If the freight overhangs the pallet, measure the freight, not the pallet.
2. Multiply length x width x height to get cubic inches.
3. Divide by 1,728 (the cubic inches in a cubic foot) to get cubic feet.
4. Weigh the shipment as it ships — product plus pallet plus packaging. The pallet weight counts.
5. Divide total weight in pounds by total cubic feet. The result is your density in pounds per cubic foot (PCF).
6. For multi-piece shipments, add up the cubic feet of every piece and the weight of every piece first, then divide the totals — don't average per-piece densities.

Worked example: one pallet, 48 x 40 x 52 inches including the pallet, weighing 460 pounds with packaging. Cubic inches: 48 x 40 x 52 = 99,840. Cubic feet: 99,840 / 1,728 = 57.78. Density: 460 / 57.78 = 7.96 PCF. On the density scale that falls in the 6-to-under-8 PCF band — but notice how close it is to the 8 PCF break. Compress that load by two inches of height and the same pallet crosses into the next band and a cheaper class.

Tip Air is expensive. Density breaks are cliffs, not slopes — a shipment at 7.9 PCF and one at 8.1 PCF can be priced classes apart. Before booking, check how close you are to a break: shaving packaging height or consolidating cartons on fewer pallets is often worth real money.

Reading the density scale

Under the 13-tier density scale in effect since July 2025, lower density means a higher class number and a more expensive shipment. The bands run roughly as follows (always confirm current breaks with your carrier or the NMFC itself):

• 50 PCF or more: class 50 — the densest, cheapest freight
• 35 to under 50 PCF: class 55
• 30 to under 35 PCF: class 60
• 22.5 to under 30 PCF: class 65
• 15 to under 22.5 PCF: class 70
• 12 to under 15 PCF: class 85
• 10 to under 12 PCF: class 92.5
• 8 to under 10 PCF: class 100
• 6 to under 8 PCF: class 125
• 4 to under 6 PCF: class 175
• 2 to under 4 PCF: class 250
• 1 to under 2 PCF: class 300
• Under 1 PCF: class 400 — the lightest, most space-hungry freight

So the 7.96 PCF example above is class 125. Repack the same 460 pounds to 44 inches tall and the volume drops to 48.89 cubic feet, the density rises to 9.41 PCF, and the shipment becomes class 100. Eight inches of dead air in the packaging was holding it a full class higher.

Avoiding reclassification fees

Carriers run freight across dimensioners and scales routinely. If their measured density puts you in a different class than your BOL claims, you get a reweigh/reclass adjustment — the corrected freight charges plus, often, an inspection fee. Disputes are winnable only with documentation from before pickup.

• Measure and weigh every shipment as packed, not from the product spec sheet.
• Keep a dated density worksheet per shipment: dimensions, weight, the math, and the resulting class.
• Photograph the packed pallet with a tape measure visible when the class is borderline.
• Put accurate dims and weight on the BOL — understating them is what triggers inspections.
• Re-check density whenever packaging, carton counts, or pallet patterns change, even for a product you ship constantly.

Common questions

Related guides