The short answer
- Freight class is a pricing category for LTL freight, set by the NMFC item for the commodity being shipped.
- For most goods, density estimates the class on a 13-tier scale, and density is figured per handling unit from its measured size and weight.
Who sets freight class?
The National Motor Freight Traffic Association, the NMFTA, publishes the National Motor Freight Classification, the NMFC. The NMFC assigns a class to commodities through items: each item covers a described kind of goods and states the class that applies to it. When a carrier rates an LTL shipment, the item for the commodity on the bill of lading is the authority for the class.
Density enters the picture because many items rate by density, and because a shipper often needs a class before the item is looked up. For most goods, figuring the density of the handling unit and reading the class off the NMFC density scale gives a sound estimate. The estimate is a starting point for a quote and a check on the bill of lading. It is not a replacement for the item.
The freight class calculator runs the density math and returns the class the scale gives for your shipment. Treat the result as an estimate. If the NMFC item for your commodity assigns a different class, the item governs the billed class, and the estimate is the number that tells you to go and check the item.
The NMFC also sets the method behind the estimate. NMFC Item 110 covers how density is figured, per handling unit, from the unit's measured size and weight. The next section walks through that method and the scale it feeds.
How does density turn into a class?
Density is figured per handling unit. Measure the greatest straight-line length, width and height of the unit, including projections and the pallet. Multiply the three measurements for cubic inches, then divide by 1,728 to get cubic feet. Divide the unit's weight by the cubic feet. The result is the density in pounds per cubic foot, and the density scale turns that number into a class.
Worked example: a pallet measures 48 × 40 × 50 inches and weighs 600 lb. The volume is 96,000 cubic inches, which is 55.56 cubic feet. The density is 600 ÷ 55.56, which is 10.80 lb per cubic foot. On the scale, 10.80 falls in the band from 10 to under 12, so the estimated class is 92.5.
The bands include the lower number and exclude the upper one. A density of exactly 12 lb per cubic foot falls in the 12 to under 15 band and takes class 85, not 92.5. That is also the direction density work pays in: adding weight to the same footprint, or shrinking the footprint under the same weight, raises the density and can drop the class. The pallet above at 12 lb per cubic foot rates 85 instead of 92.5.
The full scale is below, and the same table is on the freight class chart page with the calculator.
| Density (lb per cubic foot) | Freight class |
|---|---|
| Under 1 | 400 |
| 1 to under 2 | 300 |
| 2 to under 4 | 250 |
| 4 to under 6 | 175 |
| 6 to under 8 | 125 |
| 8 to under 10 | 100 |
| 10 to under 12 | 92.5 |
| 12 to under 15 | 85 |
| 15 to under 22.5 | 70 |
| 22.5 to under 30 | 65 |
| 30 to under 35 | 60 |
| 35 to under 50 | 55 |
| 50 or more | 50 |
NMFC density scale, NMFTA Disposition Bulletin 1371, Docket 2025-1, effective July 19, 2025. Bands include the lower number and exclude the upper number.
Why are some classes not on the density scale?
The density scale has 13 classes, and the NMFC uses more classes than that. Classes 77.5, 110, 150, 200 and 500 do not appear on the scale at all. They exist only as assignments in specific NMFC items for specific commodities. A density estimate never returns them, because the scale has no band that produces them.
If the item for your commodity assigns class 150, the shipment bills at 150 even if its density reads at a band that gives 100. The reverse holds as well: a dense shipment does not earn class 50 by density alone if its item assigns a higher class. This is the most common reason a billed class differs from a calculator result, and it is a difference in authority, not an error in the math.
Three other factors can move a shipment off its density class. Handling covers freight that needs extra care or work to load and move. Stowability covers how a shipment fits with other freight in the trailer, including freight that cannot bear weight stacked on it or that wastes space around it. Liability covers the risk the carrier takes on if the freight is lost or damaged, which rises with the value of the goods. The NMFC item for a commodity weighs these factors along with density, which is why two shipments at the same density can carry different classes.
What changed in 2025 and 2026?
The density scale itself is new. Docket 2025-1, issued as NMFTA Disposition Bulletin 1371, replaced the old scale with the 13-tier density scale shown above, effective July 19, 2025. Shippers who had worked from the old scale had to recheck their stored classes against the new bands, because the same density could land on a different class under the new scale.
Two more dockets followed. Docket 2026-1 took effect on May 23, 2026. Docket 2026-2 takes effect on December 12, 2026. Neither docket changed the 13-tier density scale. The bands and the classes on the scale are the same after both 2026 dockets as they were in July 2025.
The items are another matter. Individual commodity items keep moving between classes from docket to docket, as the NMFTA reviews commodities and reassigns them. A class copied from an old template can be stale even when the scale is not, because the item behind the template moved. The practical rule is short: trust the scale from July 2025, and recheck the item for any commodity you ship each time a new docket takes effect.
Questions
How do I find the freight class of my shipment?
Start with the NMFC item for the commodity, which states the class that governs the bill. If you need a number before the item is checked, figure the density of the handling unit and read the class off the density scale or the freight class calculator.
Why did my billed class differ from the density estimate?
The NMFC item governs the billed class, and the item can assign a class the density scale never returns, such as 110 or 150. Handling, stowability and liability can also move a shipment off its density class. The estimate is a check, not the authority.
Did the density scale change in 2026?
No. Docket 2026-1 took effect on May 23, 2026 and Docket 2026-2 takes effect on December 12, 2026, and neither changed the 13-tier scale from July 2025. Individual commodity items moved between classes in both dockets, so stored item classes can still be stale.
Sources
- NMFTA Disposition Bulletin 1371, Docket 2025-1
- NMFTA Disposition Bulletin 1373, Docket 2026-1
- NMFTA Disposition Bulletin 1374, Docket 2026-2
- NMFC Item 110, density method
Rules last checked: November 12, 2026
This guide is general information, not legal or accounting advice. The NMFC item for your commodity governs the billed class.