Not on the current density scale
Class 500 exists as a class number, but no band of the current NMFC density scale produces it. If a calculator hands you 500 from a density, it is reading an obsolete chart.
An older, finer-grained density guideline — still hard-coded into a number of free calculators — mapped under 1 pcf to class 500. The current NMFC density scale does not. Density in that range falls in the same under-1 pcf band and rates class 400.
The number has not been abolished. Specific NMFC items can still carry class 500, and it can legitimately appear on a rate sheet for that reason. What it cannot be is the output of a density calculation.
It is running the old guideline. That is not a cosmetic difference: the two charts map the same shipment to different classes and therefore different rates. A BOL tendered at class 500 on density grounds invites a reclass at the terminal, billed after the fact at the corrected class plus a correction fee.
We tested this. As of August 2026, several widely-used free freight class calculators still return 500 for under 1 pcf freight — see the calculator audit for the reproducible test results.
| Obsolete guideline | Current NMFC scale | |
|---|---|---|
| Density | under 1 pcf | under 1 pcf |
| Class | 500 | 400 |
Thirteen sub-provisions, running from class 50 for freight at 50 pcf and above down to class 400 for freight under 1 pcf. NMFC Docket 2025-1, effective 19 July 2025, expanded the previous 11-sub scale to 13: it narrowed the top band to 30–35 pcf at class 60, and added class 55 for 35–50 pcf and class 50 for 50 pcf and over. The full table is on the freight class chart.