Written by the America’s Driving Force team · Reviewed by Joel Curtis, retired professional truck driver · Published October 5, 2026 · Last reviewed October 5, 2026 · Sources are listed at the end
Under 49 CFR 383.91, Class A covers combinations with a rating of 26,001 pounds or more where the towed unit is rated over 10,000 pounds. Class B covers a single vehicle rated 26,001 pounds or more, towing no more than 10,000 pounds. A Class A holder with the right endorsements may also drive Class B and Class C vehicles, but not the reverse.
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The short answer
The short answer: Class A covers combinations of vehicles where the trailer or towed unit is heavy, while Class B covers a single heavy vehicle, such as a straight truck or a large bus. A Class A license lets you drive what a Class B license lets you drive (with the right endorsements), but not the other way around. The federal definitions are in 49 CFR 383.91, and this guide explains them in plain language.
The weights below come from the regulation as it appeared on eCFR on October 5, 2026. A weight rating is the number the manufacturer specifies, not what the vehicle weighs on a given day. This guide updates an older version that described Class B as limited to a “10,001 lbs or lighter payload” and gave Class C a different meaning than the regulation does.
How federal rules define Class A, B and C
Federal rules sort commercial motor vehicles (CMVs) into three groups. Under 383.91(a) and the definition of a CMV in 49 CFR 383.5:
| Class | Federal group name | What it covers |
|---|---|---|
| Class A | Combination vehicle (Group A) | Any combination of vehicles with a gross combination weight rating (GCWR) of 26,001 pounds or more (11,794 kg), provided the gross vehicle weight rating (GVWR) of the vehicle or vehicles being towed is more than 10,000 pounds (4,536 kg). |
| Class B | Heavy straight vehicle (Group B) | Any single vehicle with a GVWR of 26,001 pounds or more, or any such vehicle towing a vehicle that does not exceed 10,000 pounds GVWR. |
| Class C | Small vehicle (Group C) | Any single vehicle or combination that meets neither the Group A nor the Group B definition, but that is designed to transport 16 or more passengers including the driver, or is used to transport hazardous materials as defined in 49 CFR 383.5. |
In practice, that means a tractor-trailer combination heavy enough to meet the Group A weight test is Class A. A heavy single truck, such as a straight truck, is Class B. Those weight numbers are what the rule uses, not the vehicle’s name or type of work.
What actually separates Class A from Class B
The main thing that separates A from B is the towed unit. A Class A combination needs a combined rating of at least 26,001 pounds and a towed unit rated above 10,000 pounds. A Class B vehicle is a single vehicle rated at 26,001 pounds or more, and the regulation allows it to tow something rated at 10,000 pounds or less. The older version of this page said a Class B holder could only carry a payload of 10,001 pounds or lighter. That is not what the regulation says: the 10,000 pound figure is about the GVWR of a towed vehicle, not the cargo carried.
The regulation’s definitions do not list job titles or typical vehicles in the text we read, so check with your state driver licensing agency or the employer when you need to know whether a specific vehicle falls into Group A or Group B. The group depends on the manufacturer’s ratings, and the test vehicle is judged by its GVWR or GCWR rather than its actual weight, according to 49 CFR 383.133.
Which license covers which vehicles
Under 383.91(c), a driver who wants to operate in a different vehicle group than the one on their CDL must retake and pass all the related tests, with two exceptions:
- 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), if they have the required endorsements.
- A driver who passed the tests for a heavy straight vehicle (Group B) may operate any small vehicle (Group C), if they have the required endorsements.
So a Class A license covers Class B and Class C vehicles too, which is why people who are unsure what they will drive often start there. A Class B license does not cover a Group A combination, and moving up means passing the Group A tests. The federal training rules for first-time applicants also include upgrading from Class B to Class A; see our guide to entry-level driver training.
Endorsements and restrictions
Your license class is only part of what you may drive. 49 CFR 383.93 requires state-issued endorsements to operate vehicles that are double or triple trailers, passenger vehicles, tank vehicles, vehicles used to transport hazardous materials, or school buses. The endorsement tests are a knowledge test for double/triple trailers, tank vehicles and hazardous materials, and a knowledge and a skills test for passenger and school bus endorsements.
Restrictions also depend on how you test. Under 383.135(b), if you take the skills test in a vehicle without air brakes, with air over hydraulic brakes, or with an automatic transmission, a restriction is placed on the license. A driver who takes the test in a combination vehicle with a non-fifth wheel connection receives a tractor-trailer restriction. And a driver who fails the combination vehicle portion of the knowledge test must not be issued a Group A permit or license.
How to choose
To choose between the classes, start with the vehicle you expect to drive and read its manufacturer’s ratings. If you plan to pull a heavy trailer, the Group A definition is the one that applies. If you plan to drive a single heavy vehicle, Group B is the definition in the regulation. If you are unsure, remember that Group A holders may also operate Group B and Group C vehicles with the right endorsements, which is the reason many applicants choose it. Your state licensing agency can confirm what applies where you live, and may have extra requirements.
Next steps: read our guides on federal CDL training requirements and what CDL training costs, use our CDL training page to compare schools, and browse trucking companies by state. Regulations change, so confirm current details with FMCSA or your state.
Frequently asked questions
What is the main difference between a Class A and Class B CDL?
Class A covers combinations of vehicles with a combined rating of 26,001 pounds or more where the towed unit is rated over 10,000 pounds. Class B covers a single vehicle rated 26,001 pounds or more, or one towing a unit rated 10,000 pounds or less.
Can I drive a Class B vehicle with a Class A CDL?
Yes. Under 49 CFR 383.91, a driver who passed the knowledge and skills tests for a combination vehicle may operate a heavy straight vehicle or small vehicle, provided they have the requisite endorsements.
Can I drive a tractor-trailer with a Class B CDL?
Not if it falls within the Group A definition. A Group B license covers a single heavy vehicle, or one towing a unit rated at 10,000 pounds or less. Moving to Group A means passing the Group A tests.
What does Class C mean for a CDL?
Group C is a vehicle that meets neither the Group A nor Group B definition but is designed to carry 16 or more passengers including the driver, or is used to transport hazardous materials as defined in 49 CFR 383.5.
Do weight ratings mean the vehicle's actual weight?
No. The class depends on the manufacturer's gross vehicle weight rating or gross combination weight rating. For skills tests, 49 CFR 383.133 says the rating, not the actual weight, is used to decide whether a vehicle is representative.
Related guides
- How to get a CDL without a traditional truck driving school
- How much does CDL training cost?
- Trucking companies by state
About the reviewer
Joel Curtis is a retired professional truck driver with more than 30 years of over-the-road experience in Canada and the United States. He reviews our guides for practical accuracy from a driver’s point of view. Every guide is built from the official sources listed below.
Sources
- 49 CFR 383.91: Commercial motor vehicle groups, Electronic Code of Federal Regulations
- 49 CFR 383.5: Definitions, Electronic Code of Federal Regulations
- 49 CFR 383.93: Endorsements, Electronic Code of Federal Regulations
- 49 CFR 383.135: Passing knowledge and skills tests, Electronic Code of Federal Regulations
This guide is general information, not legal or financial advice. Rules, fees and requirements change, so confirm current details with the agencies listed above and your state before you act.