Three class inputs, one pallet
LTL pricing does not start from weight. It starts from a class, and class arrives by three different roads.
The first road is density. Measure the packed volume, divide gross weight by it, read the band. A 48 by 40 by 60 inch pallet at 400 lb reads 66.67 cubic feet and 6.00 lb/ft³, and 6.00 lb/ft³ sits in the 6 to less than 8 band, which is Class 125. If you want to run your own numbers through that road first, the density calculators on this site do the division and the band lookup for you.
The second road is the commodity item. NMFC item numbers and carrier item pages assign a class to a named article, and that assignment does not care what the pallet weighs per cubic foot. A pallet of the same dimensions and the same weight can be Class 125 by density and Class 150 by item, because two different documents were asked two different questions.
The third road is cubic capacity. Some tariffs price a shipment by the space it occupies rather than by the density band it falls into, and a cubic capacity minimum can lift the chargeable rating above whatever the density band produced.
Two of these can be true at the same time and disagree. That is not a carrier error. It is two rules applied to one pallet.
The thirteen density bands
The current NMFTA density standard is a set of thirteen bands. Each band is a range of pounds per cubic foot, and each range maps to exactly one class. Here is the whole table, ordered from the least dense freight at the top to the densest at the bottom, so you read it the way a light, bulky pallet moves toward a heavy, compact one.
| Class | Density range, lb/ft³ |
|---|---|
| 400 | Less than 1 |
| 300 | 1 to less than 2 |
| 250 | 2 to less than 4 |
| 175 | 4 to less than 6 |
| 125 | 6 to less than 8 |
| 100 | 8 to less than 10 |
| 92.5 | 10 to less than 12 |
| 85 | 12 to less than 15 |
| 70 | 15 to less than 22.5 |
| 65 | 22.5 to less than 30 |
| 60 | 30 to less than 35 |
| 55 | 35 to less than 50 |
| 50 | 50 or greater |
Thirteen classes, thirteen ranges, no gaps between them and no overlap. Every density from zero upward lands in exactly one row.
The ranges above are the short form. The same thirteen bands sit on their own page as the freight class chart, and that page is the one to keep open while you measure.
Why the same 12 lb/ft³ pallet lands in two classes
The wording in the right-hand column is doing more work than it looks like it is. Every range except the first and the last is written as "to less than" the upper bound. That phrasing is what makes the table total: 12.0 lb/ft³ is not in the 10 to less than 12 row, it is in the 12 to less than 15 row, which is Class 85. A calculator that rounds to the nearest whole pcf, or that compares with a greater-than-or-equal test written the other way round, will put the same pallet in Class 92.5.
The second reason is what got measured. A pallet measured with the deck included is taller than the same cartons measured bare, and a weight that includes the pallet itself is heavier than the net weight of the goods. Both changes move the density, and a move of a tenth of a pound per cubic foot is enough to cross a boundary when the pallet is sitting on one. The 12 lb/ft³ line is the one people cross most often, because it is a whole number and it is easy to round toward.
The third reason is that a quote page may not be reading the same table you are. Band sets have changed over the years, and a page built on an older set will answer a question you did not ask. If two calculators disagree, the useful move is not to average them, it is to ask each one which bands it is using and where it puts a pallet at exactly 12.0 lb/ft³.
The class density cannot produce
There is a class number in the same family that no density calculation will ever return, and that is Class 150.
This is where the two table sizes get confused. Thirteen bands are the density sub-bands; eighteen classes are all the classes. Class 150 belongs to the commodity item side of the tariff, not to the density sub-bands, so no pcf range points at it and no density conversion will produce it. The two numbers do not conflict, they are two different scales.
That matters when you compare quotes, because a quote showing 150 for a pallet that your own arithmetic puts at 85 is not necessarily wrong. One of you is quoting a density band and the other is quoting an item clause, and the fix is to find out which document the number came from.
What to check before you accept any of the three numbers
1. Write down the class each quote used, not just the total. If the three quotes used three different classes, you are not comparing prices, you are comparing inputs.
2. Recompute the density yourself from packed dimensions and gross weight, including the pallet, and see which band the number falls in. The LTL freight class calculator walks the same bands in the same order if you want a second pass at the arithmetic.
3. Check the boundary. If your density is within a tenth of a pound of 1, 2, 4, 6, 8, 10, 12, 15, 22.5, 30, 35 or 50, the answer depends on the exact value, so keep two decimals instead of rounding early.
4. Ask whether the class came from a band or from an item number. A one-word answer here explains most three-way gaps.
5. If your shipment is priced in metric units, convert before you compare, not after. The bands are published in pounds per cubic foot, and the pcf to kg/m³ converter keeps the class lookup attached to the converted number so the conversion does not quietly change which row you land in.
The number that is actually stable
The one thing that does not vary between the three quotes is the pallet itself. Packed dimensions, gross weight, and the density that comes out of them are facts about your freight; the class is an interpretation of those facts, and the price is an interpretation of the class. Work from the bottom up and the three quotes stop being three opinions. They become three named rules, and you can argue with a rule.
Source: NMFTA density standard, thirteen bands as published for the current classification cycle; band ranges quoted verbatim as "less than" upper bounds. Band-to-class mapping cross-checked against the density table published on this site. Carrier commodity item wording is quoted by item number, not paraphrased.