What Is an MC Number and Why Is It Required for Truckers?

In the trucking industry, staying compliant with federal regulations is a non-negotiable part of running a legitimate operation. One term that comes up early in that process is the MC number—a key credential that’s often confused with a DOT number, but serves a distinct and essential role.

If you’re planning to operate as a for-hire carrier, understanding what an MC number is—and whether you need one—is critical before you hit the road.

What Is an MC Number?

An MC number, short for Motor Carrier number, is issued by the Federal Motor Carrier Safety Administration (FMCSA). It grants a trucking company the legal authority to transport cargo or passengers for compensation across state lines.

While a DOT number is used to track safety and compliance data, the MC number is specifically tied to operating authority. If you’re getting paid to haul freight or move people from one state to another, this number isn’t optional—it’s required by law.

Who Needs an MC Number?

You need an MC number if you meet both of the following conditions:

  • You are a for-hire motor carrier, meaning you’re getting compensated for transporting goods or passengers.

  • You are engaged in interstate commerce, which includes any activity that crosses state lines, even if the trip itself doesn’t.

There are also specific requirements for different types of operating authority—such as carriers transporting household goods or certain commodities. The FMCSA determines what kind of MC number applies based on your type of operation and cargo.

If you’re only operating within a single state (intrastate) and not hauling federally regulated commodities, an MC number may not be necessary. However, it’s not always that simple. Some states have additional requirements, and certain exemptions may apply. It’s worth confirming your specific situation before proceeding.

The Difference Between DOT and MC Numbers

Though they’re often applied for at the same time, a DOT number and an MC number are not interchangeable.

  • The DOT number is used for monitoring safety compliance, vehicle inspections, and crash history.

  • The MC number gives you the legal authority to operate as a for-hire carrier across state lines.

Most for-hire carriers need both.

How to Get an MC Number

Applications are processed through the FMCSA’s Unified Registration System (URS). When applying, you’ll be required to provide information about your business structure, the type of freight you intend to haul, and your insurance coverage.

After submitting your application, a waiting period—usually 21 calendar days—is imposed before your authority becomes active. During that time, your application is made public, and the FMCSA allows for any protests or challenges.

It’s not enough to simply apply—you also need to:

  • File proof of insurance with the FMCSA from an authorized insurance provider

  • Designate a process agent for every state in which you operate, using Form BOC-3

If either of these steps is missed, your MC number will not become active—even after the waiting period.

Why It Matters

Without an active MC number, you are not legally allowed to operate as a for-hire carrier across state lines. Carriers found operating without one can face significant fines and be ordered out of service.

In addition to regulatory consequences, lacking an MC number can limit your access to certain brokers, load boards, and shippers who verify operating authority before offering contracts. It’s a foundational requirement in building credibility as a carrier.

Maintaining Compliance

Once your MC number is active, you’ll need to keep your filings current and your insurance up to date. Changes to business structure, address, or operation type must be reported to the FMCSA. Failure to do so can result in suspension or revocation of your authority.

Your MC number also ties into your business’s compliance history, making accurate recordkeeping and consistent operations essential.