MC Number vs. DOT Number: What's the Difference?

New carriers are often confused by the two numbers the federal government uses to track them. They sound similar, they're issued by the same agency, and many companies have both — but they do different jobs. Here's the difference in plain terms.

The USDOT number: identity

A USDOT number is a unique identifier the FMCSA uses to track a company's safety record — inspections, crashes, audits, and compliance reviews. Think of it as your company's federal ID for safety. Companies that operate commercial vehicles in interstate commerce (and many intrastate operators, depending on the state) are required to have one.

The MC number: operating authority

An MC (motor carrier) number — sometimes called a docket number — represents your operating authority: the legal permission to transport regulated commodities, or passengers, in interstate commerce for compensation. The MC number is what's tied to your authority letter. If the USDOT number is identity, the MC number is permission.

Do you need one or both?

Your operation	Typically needs
For-hire carrier of regulated property across state lines	USDOT number + MC number
Broker or freight forwarder	MC number (and USDOT in most cases)
Private carrier hauling only your own goods interstate	USDOT number (often no MC number)
Carrier of exempt commodities only	USDOT number (MC number often not required)

Requirements vary by commodity, geography, and operation type. Always confirm your specific obligations with the FMCSA.

How this connects to your authority letter

Because the MC number carries your operating authority, it's the number that appears on your authority letter — and the one brokers and shippers ask for when they want proof you can legally haul their freight. When you need to verify a carrier or produce your own document, you'll search by MC number.

Search your MC number to retrieve your authority letter.