CDL A vs CDL B: Which Do You Need? (2026)
CDL-A covers tractor-trailers and is the more versatile license; CDL-B covers heavy single vehicles. Both require FMCSA-approved ELDT theory — DLA's online theory is $20.
The core difference: combination vs single vehicle
A CDL-A (Class A) license is for combination vehicles — a power unit and a towed unit together — with a gross combination weight rating (GCWR) of 26,001 lb or more, where the trailer being towed is over 10,000 lb. In plain terms, that's the tractor-trailer / 18-wheeler category. A CDL-B (Class B) license is for a single heavy vehicle rated 26,001 lb or more, or one towing a unit of 10,000 lb or less. Straight trucks, large buses, dump trucks, and box trucks are typical CDL-B vehicles.
The dividing line is the trailer: if you're pulling a heavy towed unit over 10,000 lb behind a heavy power unit, you need CDL-A. If your vehicle is heavy but driven as a single unit (or pulls only a light trailer), CDL-B covers it. Both license classes are entry-level training-regulated, so whichever you choose, FMCSA-approved ELDT theory applies — see our What Is ELDT? guide for the federal background.
CDL-A is more versatile
CDL-A is the broader credential. A CDL-A holder can generally operate CDL-B vehicles as well, which means a single Class A license opens both tractor-trailer jobs and most straight-truck and bus roles. That versatility is why CDL-A is the default recommendation for drivers who want the widest range of work and the highest earning potential, including premium freight that pairs with endorsements.
If your career goal is over-the-road or regional tractor-trailer driving, choose CDL-A and start with the CDL-A Theory ELDT course. If you only ever plan to drive a specific single vehicle — a city bus, a local dump truck, a delivery box truck — CDL-B may be all you need, and the CDL-B Theory ELDT course covers that path. When in doubt, CDL-A gives you more options for the same training step.
Both classes require ELDT theory PLUS behind-the-wheel
Whichever class you pick, the federal ELDT rule (effective February 7, 2022) requires two parts: FMCSA-approved theory training AND behind-the-wheel (BTW) training. They are separate requirements. DLA provides the theory portion online for $20 — completed in under 2 hours — for both CDL-A and CDL-B.
The behind-the-wheel portion is done separately at a local FMCSA-registered provider, where an instructor evaluates your driving on a range and on public roads. DLA does not provide BTW — we handle the theory half so you can knock it out fast and cheap, then complete BTW locally. For how the two costs add up overall, see How Much Does a CDL Cost?.
After your license: add endorsements
Your license class sets what vehicle you can drive; endorsements unlock what freight you can haul. Because a CDL-A holder can pull the widest range of trailers (including tankers), endorsements often pay off more on a CDL-A. The highest-paying add-on is typically Hazmat — see What Is the Highest-Paying CDL Endorsement? and Which CDL Endorsement Should I Get? to plan your stack.
If you know you'll want Hazmat, Passenger, or School Bus, you can complete those ELDT theory courses now too — the 3-endorsement bundle is $50 versus $20 each. Endorsement ELDT is separate from your CDL-A or CDL-B theory, but you can do them in the same sitting to get road-ready faster.
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