USDOT and MC Number: The Difference and Who Needs Each

Of the USDOT and MC number, the USDOT number is the free, permanent identifier FMCSA assigns to track a carrier's safety record, inspections, crashes and audits over time. An MC number (Motor Carrier number) is a separate, paid form of federal operating authority that most for-hire carriers need to haul regulated freight or passengers across state lines. You can need a USDOT number without ever needing an MC number, but you can't get an MC number without a USDOT number first.

The USDOT requirement is broad. It generally applies to any commercial motor vehicle in interstate commerce, and many states require it for intrastate carriers as well. The number is free and doesn't expire, though FMCSA requires biennial updates to keep the registration information current.

The MC requirement is narrower and applies to for-hire carriers: businesses that haul someone else's freight or passengers across state lines for pay. A private fleet hauling only its own goods, or a carrier operating strictly within one state, typically needs a USDOT number but no MC number. Each authority type carries a one-time, non-refundable $300 fee, filed through FMCSA's registration system.

You need a USDOT number if your company runs a commercial vehicle in interstate commerce and that vehicle meets one of FMCSA's thresholds: a gross vehicle weight rating, gross combination weight rating or actual weight of 10,001 pounds (4,536 kg) or more, whichever is greater; designed or used to carry more than 8 passengers, including the driver, for compensation; or designed or used to carry more than 15 passengers, including the driver. A carrier hauling hazardous materials in quantities that require a safety permit needs one even for trips inside one state.

Interstate commerce, as FMCSA defines it, includes any trip between a US state and a place outside the United States, so a Canadian carrier whose qualifying trucks enter the US meets the test from its first crossing. It also covers a trip between two points in one state that passes through another state or country, or that is part of a shipment starting or ending outside the state. Several states, including California, New York, Ohio, Pennsylvania and Texas, also require a USDOT number from intrastate carriers. FMCSA keeps the full list, and its USDOT Wizard answers the question for your own operation.

You apply online in Motus, the USDOT registration system FMCSA launched in 2026 to replace its older registration systems. If you are unsure whether you need only a USDOT number or operating authority as well, run the USDOT Wizard first. Then create a user profile in Motus, which uses Login.gov and an identity verification check, set up a company account, and apply for the USDOT number and any operating authority from that account. FMCSA no longer accepts paper transactions.

Motus is also where a registered carrier submits its biennial update, changes its name or address and adds authority later. A carrier that already had a USDOT number claims it in Motus by linking the existing record, using the same Login.gov email the company official used in the old FMCSA Portal. During the move to Motus, FMCSA temporarily suspended enforcement of biennial updates and of USDOT number inactivation, so check its registration page for the current status before you count on that pause.

You need an active USDOT number before you apply for an MC number, because the MC application builds on the existing USDOT registration. An application for operating authority without an active USDOT number gets rejected, so check your USDOT status first and don't assume it's handled. That saves you a wasted application cycle.

One technical point: the Motor Carrier docket number, the formal name behind an MC number, was never a standalone regulatory requirement. It exists to track a specific operating authority record and does not identify a person or company apart from that authority. FMCSA has proposed no longer assigning MC numbers and marking each authority with a suffix to the USDOT number instead; that change would come through a rulemaking and was not part of the first release of its new registration system. In practice, most for-hire interstate carriers end up needing both numbers active and in good standing.

Everyone asks about the USDOT and MC numbers, but a new carrier collects several more in its first year. Knowing what each one is for keeps you from paying for one you don't need.