The three CDL classes are Class A, Class B, and Class C, and each one permits you to operate different types of vehicles based on weight and configuration

A Commercial Driver's License (CDL) is divided into three classes in all 50 states. The class you hold determines the maximum weight of vehicle you can legally operate and what kind of cargo or passengers you can transport. The difference between them comes down to the vehicle's Gross Vehicle Weight Rating (GVWR)—the maximum weight the manufacturer says the vehicle can safely carry when fully loaded—and whether you're towing a trailer.

You cannot straightforward choose the class you want. Your state's Department of Motor Vehicles will issue you the class that matches the vehicle you pass your driving test in. If you later need to operate a heavier vehicle, you must take the test again in that vehicle to upgrade your license.

Key Takeaways

  • Class A CDLs cover the heaviest vehicles, including tractor-trailers and any combination where the towed unit weighs more than 10,000 pounds.
  • Class B CDLs are for single vehicles over 26,001 pounds GVWR, such as straight trucks and large buses, but you cannot tow a trailer heavier than 10,000 pounds.
  • Class C CDLs explore to smaller commercial vehicles that don't meet Class A or B weight thresholds but still require a CDL because of passenger count or hazmat cargo.
  • Your state issues the class based on the vehicle you test in, so upgrading requires a new test in a heavier or different vehicle.
  • All three classes require passing a written knowledge test, a skills test, and a medical examination before you can legally operate that class of vehicle.

Class A: Tractor-Trailers and Heavy Combination Vehicles

A Class A CDL is the highest tier and covers the largest vehicles on the road. You can operate any combination of vehicles where the towed unit (trailer) has a GVWR of more than 10,000 pounds. This includes the classic tractor-trailer setup—a powered tractor unit pulling a 53-foot semi-trailer—but also other heavy combinations like a truck towing a large enclosed trailer or a fifth-wheel RV setup.

Class A also allows you to operate any Class B or Class C vehicle, so it is the most versatile license. However, it requires the most extensive testing. You must pass the general knowledge test, the air brakes test (if your vehicle has air brakes), and a combination vehicle test, plus the behind-the-wheel skills test in an actual tractor-trailer or similar combination vehicle.

Most long-haul trucking jobs, regional delivery routes, and heavy hauling operations require a Class A CDL. If you plan to operate any vehicle where the trailer weighs more than 10,000 pounds, this is the class you need.

Class B: Single Heavy Trucks and Large Buses

A Class B CDL covers single vehicles (not towing a heavy trailer) that weigh more than 26,001 pounds GVWR. This includes straight trucks like dump trucks, cement mixers, box trucks used for delivery, and large passenger buses. You can also tow a trailer, but only if that trailer weighs 10,000 pounds or less.

The Class B test is less complex than Class A because you are not testing combination vehicle handling. You take the general knowledge test, the air brakes test if applicable, and the behind-the-wheel test in the actual vehicle you will operate. Many local delivery drivers, school bus operators, and waste management drivers hold Class B licenses.

Class B also allows you to operate any Class C vehicle. If you need to upgrade from Class B to Class A later, you must take the full Class A test, including the combination vehicle portion.

Class C: Smaller Commercial Vehicles with Special Requirements

A Class C CDL covers commercial vehicles that do not meet the weight thresholds of Class A or B but still require a CDL for other reasons. The most common reason is passenger capacity: any vehicle designed to carry 16 or more passengers (including the driver) requires a Class C CDL, regardless of weight. This includes small buses, shuttle vans, and passenger transport vehicles.

Class C also applies to vehicles under 26,001 pounds GVWR that carry hazardous materials (hazmat) in quantities that require placarding. A small tanker truck carrying propane or a box truck carrying certain chemicals would fall into this category. You cannot tow any trailer with a Class C license.

The Class C test covers general knowledge and the specific endorsements your vehicle requires—such as the passenger (P) endorsement for buses or the hazmat (H) endorsement for hazardous materials. Class C is the most limited of the three and does not allow you to operate Class A or Class B vehicles.

How Weight Ratings Determine Your Class

The GVWR is printed on a label attached to the driver's side door frame of every commercial vehicle. It is not the same as the vehicle's actual weight when empty; it is the maximum safe weight when fully loaded with cargo and passengers. A truck might weigh 15,000 pounds empty but have a GVWR of 33,000 pounds, meaning it can carry 18,000 pounds of cargo.

The class boundaries are strict: a vehicle with a GVWR of 26,000 pounds does not require a CDL (it falls under non-commercial licensing), but 26,001 pounds requires at least a Class B. Similarly, if you are towing a trailer that weighs exactly 10,000 pounds, you can use a Class B license, but 10,001 pounds requires a Class A.

This is why it matters to know your vehicle's actual GVWR before you decide which license to pursue. Operating a vehicle that exceeds your license class is illegal and can result in fines, points on your record, and liability issues if you are involved in an accident.

Endorsements and Restrictions That Work Across All Classes

Your CDL class is separate from your endorsements, which are additional qualifications that allow you to operate specific types of vehicles or carry specific cargo. Common endorsements include the H endorsement (hazardous materials), the P endorsement (passengers), the T endorsement (double and triple trailers), and the X endorsement (combination of hazmat and tanker).

You can hold endorsements on any class of license. A Class B driver can have an H endorsement to carry hazmat in a straight truck, or a Class A driver can have a P endorsement to operate a tractor-trailer configured as a passenger vehicle. Endorsements are added through separate written tests and do not change your class.

Restrictions work the opposite way: they limit what you can do with your license. For example, an air brake restriction means you can only operate vehicles without air brakes, even if you hold a Class A. Restrictions are usually added when you fail the air brakes test but pass everything else, or when you test in a vehicle without air brakes.

Testing Requirements and Medical Certification for Each Class

All three classes require the same medical examination, administered by a certified medical examiner listed on the Federal Motor Carrier Safety Administration (FMCSA) National Registry. The exam checks your vision, hearing, blood pressure, and ability to safely operate a commercial vehicle. You must pass this exam before you can take any CDL test, and you must renew it every one to four years depending on your medical history.

The written knowledge tests vary by class. Class A requires four tests: general knowledge, air brakes, combination vehicles, and any endorsement tests. Class B requires three: general knowledge, air brakes, and endorsement tests. Class C requires general knowledge and endorsement tests. All written tests are administered by your state's DMV.

The behind-the-wheel skills test is the most expensive and time-consuming part. You must provide the actual vehicle you will operate, and a state examiner will test your ability to perform pre-trip inspections, basic vehicle control, and on-road driving. Many people take a CDL training course before testing, which can cost between $3,000 and $7,000 depending on the school and your location.

Frequently Asked Questions

Can I get a Class A CDL if I only want to drive local routes?

Yes. Your license class is based on the vehicle you test in, not on how you plan to use it. If you test in a tractor-trailer, you receive a Class A even if you only drive locally. However, you would be paying for more testing and licensing than necessary if a Class B vehicle would meet your needs.

What happens if I drive a vehicle that is too heavy for my license class?

Operating a vehicle that exceeds your license class is illegal. You can be cited, fined, and have points added to your driving record. If you are involved in an accident, your insurance may deny coverage because you were operating an unlicensed vehicle, leaving you personally liable for damages.

Do I need a CDL to tow a small trailer with my personal truck?

Not if the combined GVWR of the truck and trailer stays under 26,001 pounds and you are not carrying hazmat or more than 15 passengers. Once either threshold is crossed, a CDL becomes required. Check your truck's door label and the trailer's specifications to be sure.

Can I upgrade from Class B to Class A without retesting everything?

No. You must take the full Class A test, including the combination vehicle test, even if you already hold a Class B. Your previous license does not waive any portion of the Class A exam. However, your medical certification carries over if it is still valid.

What is the difference between a CDL endorsement and a CDL class?

Your class determines the weight and type of vehicle you can operate. An endorsement allows you to carry specific cargo or passengers within that class. For example, a Class A driver with an H endorsement can haul hazmat in a tractor-trailer, but a Class A driver without an H endorsement cannot, even though both can operate the same truck.