What this counts, and what it does not
The number this page returns is a packing result: how many cartons fit on one pallet, how high the stack ends, and what that stack weighs per cubic foot. It is arithmetic on the seven values you typed. It is not a rate, not a transit time and not a booking.
Two loads can carry the same forty cartons and price differently, because the price depends on lane, weight break, accessorials and the class written on the bill of lading. Use the count to plan the pallet. Use the class to open a conversation with the carrier, not to close one.
Why the pallet decides the density
Density is weight divided by the cube the carrier measures, and the carrier measures the pallet rather than the cartons. A 48 × 40 in pallet stacked to 45 in is 50.00 ft³ whether the cartons inside leave gaps or not.
That is why overhang costs twice. Let the cartons lean two inches past the stringer on two sides and the footprint becomes 52 × 42. The cube grows, the density drops, and a load that sat inside Class 85 can slide to 92.5 with no pound changing. Stretch wrap adds height the same way. Measure the finished unit, wrap and all.
A short stack works the other way. The same weight pressed into fewer cubic feet raises the density, and the class falls with it.
The class here is a default, not a verdict
The suggested class comes from the standard thirteen-band density scale. That is the answer density alone can give. It is not always the answer the tariff gives.
Some commodities are classed by what they are rather than by how dense they are. A dense item can still carry a high class because of handling, stowability or liability. When the two disagree, the NMFC item wins. The thirteen bands, in full, are on the freight class chart page.
For the whole sequence — measure, convert, check the item, and keep the record that survives a reweigh — read how to determine freight class.