CDL endorsement and restriction code decoder.

Where the letters come from

Federal rules set the minimum content of a commercial driver’s licence. Section 383.153(a) lists the vehicle group the holder may drive, the endorsements and the restrictions, and gives the letter codes for each. The letters on your licence will usually be the federal ones, but states may add codes. Under the same section, a state that uses its own code for an endorsement grouping or a restriction has to explain it on the front or back of the licence document. A code that is not in the federal list is therefore not necessarily an error; look for the explanation on the card.

The three vehicle groups

Section 383.91(a) defines the groups, which most people call classes. Group A is any combination of vehicles with a gross combination weight rating of 26,001 pounds or more, provided the vehicle being towed is rated over 10,000 pounds. Group B is any single vehicle rated 26,001 pounds or more, or such a vehicle towing a vehicle rated 10,000 pounds or less. Group C covers a vehicle or combination that is neither A nor B but 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. The regulation gives the thresholds in kilograms first (11,794 kg); the pound figures are the ones the section states for Group B. The group finder applies exactly these tests and tells you which one fired.

Endorsements

The test column comes from the list of endorsements that require testing in 383.93(c). That list names double/triple trailers, passenger, tank vehicle, hazardous materials and school bus; it does not name X, so the X row simply points back to the two endorsements it combines. A commercial learner’s permit can carry only P, S and N endorsements under 383.93(a)(2) and 383.153(b).

Restrictions

On a learner’s permit the regulation adds P (no passengers in a CMV bus) and X (no cargo in a CMV tank vehicle), alongside L, V, M, N and K. That is why the same letters appear in different columns: N is an endorsement for tank vehicles and also a restriction against Class A and B passenger vehicles, and X is an endorsement on a CDL and a restriction on a permit. The decoder keeps endorsement letters and restriction letters in separate boxes for exactly this reason.

A worked example (hypothetical licence)

A licence reads Class A, endorsements H N X, restriction L. The decoder reports Group A, Combination Vehicle; H, hazardous materials; N, tank vehicle; X, tank vehicle and hazardous materials combined; and L, no air brake equipped CMV. Note that X already combines tank vehicle and hazardous materials, so a licence showing H, N and X lists the same privileges more than once. Next, a straight truck rated 33,000 pounds towing a 14,000-pound trailer: the combination rating is 26,001 or more and the trailer is over 10,000, so Group A. Drop the trailer to 8,000 pounds and the same truck is Group B. A 20,000-pound shuttle bus designed for 24 passengers is neither A nor B by weight, but carries 16 or more passengers, so Group C. The licence and vehicle are invented for illustration.

Common mistakes

• Reading N as the same thing in both boxes. It is a tank endorsement or a passenger restriction.
• Assuming every state uses only federal codes. States may add their own, explained on the card.
• Treating the group finder as a licensing decision. It applies the weight tests in the regulation to what you type.
• Reading a restriction as optional. It limits what the holder may drive, and a state can add its own.

Who this is for

New drivers reading a first licence, dispatchers and safety staff checking that a driver matches the load, and recruiters sorting applicants by class and endorsement.

What this page does not cover

• It does not read licence numbers or check whether a licence is valid. CDL numbers are state-specific and not decoded here.
• It does not decode state-defined codes, which are explained on each state’s licence.
• It does not cover medical certification, entry-level driver training or fees.
• It stores and sends nothing you type.