Class A vs Class B CDL: Weights and Written Tests

A Class A CDL is for a combination of vehicles with a gross combination weight rating (GCWR) of 26,001 pounds or more, when the GVWR of the vehicle being towed is in excess of 10,000 pounds. A Class B CDL is for a single vehicle with a GVWR of 26,001 pounds or more. The big difference is the towed unit.

The federal rule calls these Group A and Group B. States use the word "class." They mean the same thing here.

Class A vs Class B at a glance

GCWR is the gross combination weight rating. GVWR is the gross vehicle weight rating. The manual defines GVWR as the value the manufacturer specifies as the loaded weight of a single vehicle. It is a rating, not what the truck weighs on a scale.

The manual also says a bus can be Class A, B or C, depending on weight and whether it is a combination vehicle.

What a Class A license allows

The regulation, 49 CFR 383.91(c)(1), says a driver who passed the knowledge and skills tests for a combination vehicle (Group A) "may operate a heavy straight vehicle (Group B) or a small vehicle (Group C), provided that he/she possesses the requisite endorsement(s)."

A Class B holder can go down one step. Under 383.91(c)(2), a driver who passed the tests for a heavy straight vehicle (Group B) may operate any small vehicle (Group C), with the right endorsements. Any other change of group falls under the general rule in 383.91(c): you "retake and pass all related tests." That is why a tractor-trailer with a towed unit over 10,000 pounds GVWR needs Group A tests.

Which written tests you take

The manual's Section 1 says every applicant takes the General Knowledge test. The 2026 Virginia edition and the 2014 Massachusetts edition read the same here. Their study chart splits the classes this way:

1. Class A: General Knowledge and Combination Vehicles. The manual says the combination vehicles test is "required if you want to drive combination vehicles."
2. Class B: General Knowledge. Section 6 is not marked for Class B.
3. Both classes: Air Brakes, if your vehicle has air brakes. The chart says to study Section 5 if you plan to operate vehicles equipped with air brakes.

Read more in our combination vehicles test guide and our air brakes test guide. For the full list by class and endorsement, see which CDL tests do I need.

Endorsements are separate

Class A and Class B do not include endorsements. Under 49 CFR 383.93, you need a state endorsement to operate double or triple trailers, passenger vehicles, tank vehicles, vehicles that carry hazardous materials, and school buses. Doubles/triples, tank and hazmat each need a knowledge test. Passenger and school bus need a knowledge test and a skills test.

The manual lists the Doubles/Triples test as required if you want to pull double or triple trailers. That is a separate test from Combination Vehicles.

Restrictions that follow your test truck

You take the skills test in the type of vehicle you want to be licensed for. Two rules in 49 CFR 383.95 matter here:

• If you take the skills test in a truck without air brakes, or fail the air brake part of the knowledge test, your license is restricted from any vehicle with air brakes.
• If you take a Class A skills test in a combination with a pintle hook or other non-fifth wheel connection, you are restricted from operating a tractor-trailer connected by a fifth wheel that requires a Group A CDL.

How to pick a class

Check the weight rating on the vehicle you plan to drive. Then ask whether it pulls a trailer, and how heavy that trailer's rating is. If the combination is rated 26,001 pounds or more and the towed unit is rated over 10,000 pounds, that is Class A. If it is a single vehicle rated 26,001 pounds or more, that is Class B. A Class B vehicle may tow a unit of 10,000 pounds GVWR or less.

Your state's manual and licensing office have the final say on which tests apply to you. Check them before you book.

Try 10 exam-style questions built from the official CDL manual.