MC number
An MC number (motor carrier number, also called a docket number) is the identifier FMCSA assigns to a company's grant of operating authority: the legal permission to transport regulated freight for hire in interstate commerce. One company has one USDOT number, but it can be associated with more than one docket number if it obtained different authorities over time.
Why it still matters
Load boards, rate confirmations, and broker paperwork still lean on MC numbers, so an MC number is often the one you have in hand. It works fine as a lookup key. In May 2026 FMCSA moved registration to Motus. FMCSA's notice for that release says it does not eliminate MC numbers; FMCSA plans to take that up in later releases. The USDOT number is still the better identifier to anchor on.
The practical rule
Use whichever number you have; anchor your records on the USDOT number. fleetfax accepts both and resolves an MC number to its USDOT record automatically, so a search by either lands on the same carrier report.
One number, one company
If the company quoting you a load gives an MC number that resolves to a different legal name than the one on the rate con, that's worth resolving before anything else. Identity mismatches are where impersonation and double brokering tend to show up, and the federal record is the arbiter of who an MC number actually belongs to.
fleetfax reads public FMCSA data and is not affiliated with FMCSA or the U.S. Department of Transportation. This page explains terminology; it is not legal advice.
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