What is Freight Class 400? Density, Examples & Cost

Freight class 400 corresponds to a density of 1-2 pounds per cubic foot. Density is weight divided by volume, so a 60 lb shipment occupying 40 cubic feet has a density of 1.5 lbs/ft³ - squarely in the class 400 range. Compute your shipment's density with the Freight Class Calculator.

Class 400 is a very high class for very light, bulky freight. Commodities that commonly rate at this class include:

• Deer antlers and taxidermy
• Lightweight assemblies
• Inflated goods
• Very bulky low-weight cartons

These are typical examples - the binding class is always the commodity's actual NMFC provision, which you can confirm with the NMFC Lookup.

LTL carriers sell trailer space, so density drives price. Class 400 is cheaper than class 500 and more expensive than class 300. Because it sits on the light, bulky end of the scale, class 400 occupies a lot of trailer space for little weight, so the rate per hundredweight (CWT) is relatively high.

If your shipment is borderline between class 300 and class 500, packaging changes that adjust density can move it into an adjacent class and change the bill. A 60 lb shipment in 40 ft³ rates class 400 (1.5 lbs/ft³); spreading the same weight over more space lowers the density and bumps it toward class 500. Always confirm before quoting with the NMFC Lookup or the NMFC API.

Class 400's position on the freight class ladder, with its immediate neighbors:

• Class 300 (2-3 lbs/ft³) - denser than class 400, so it rates a step cheaper. Typical freight: wood cabinets and tables.
• Class 400 (1-2 lbs/ft³) - a very high class for very light, bulky freight.
• Class 500 (<1 lbs/ft³) - lighter than class 400, so it rates a step more expensive. Typical freight: ping pong balls.

Because adjacent classes are separated by narrow density bands, an inch of extra packaging or a lighter-than-expected load can shift a shipment between them - so accurate measurement matters most near these boundaries. See Freight Class Explained for the complete 18-class ladder.

You can estimate class 400 yourself in three steps before you ever request a quote:

1. Measure the packaged shipment - length, width, and height in inches, including the pallet, crating, and any overhang.
2. Convert to cubic feet and divide: volume = (L × W × H) ÷ 1,728, then density = weight ÷ volume.
3. Match the density to the chart. A result of 1-2 pounds per cubic foot lands in class 400.

Note how sensitive the boundary is: a small change in volume moves the density out of the 1-2 band and into an adjacent class. The Freight Class Calculator runs this calculation automatically, and the NMFC API returns the authoritative class for a known commodity so your TMS never has to guess.

Most class 400 billing adjustments come from two avoidable mistakes:

• Measuring the product, not the packaged unit. Class is based on the shipment as tendered - pallet, crating, and overhang included. Measuring only the product understates volume and overstates density.
• Assuming density alone. Some commodities carry a fixed NMFC class regardless of density. Verify the item's actual provision instead of trusting the density estimate.

When a carrier inspects a shipment and finds the class understated, they reclassify it and rebill the difference, frequently adding an adjustment fee. For freight near class 400, the safest workflow is to measure precisely, calculate density, and then confirm the commodity's actual NMFC provision rather than trusting a single estimate. If the density comes back just above the range, the shipment may actually rate the cheaper class 300; if it comes back just below, expect the pricier class 500.

The procedure in How to Determine Freight Class walks through measuring, calculating density, and confirming the class so a carrier inspection doesn't surprise you. To classify at scale, the NMFC API returns the class and NMFC item number for any commodity in a single call - the same data, automated for your quoting or TMS pipeline.