How Many Questions Are on the Missouri CDL General Knowledge Test?
Missouri's CDL General Knowledge test has about 50 questions, the federally standard length — but a Class A applicant training on an air-braked combination vehicle also faces two more separate tests: Air Brakes and Combination Vehicles.
Three tests, not one, for most Class A applicants
The General Knowledge test (about 50 questions) is required of every CDL applicant nationwide, set by federal regulation rather than by Missouri specifically.
The Air Brakes test (about 25 questions) and Combination Vehicles test (about 20 questions) apply on top of that for anyone training on equipment with air brakes or a combination vehicle.
All three are administered by the Missouri State Highway Patrol, the same agency that handles regular non-commercial testing.
Why this adds up to more prep than a car permit
Because each test is scored independently, a strong General Knowledge score doesn't carry over to the Air Brakes or Combination Vehicles material.
Our practice tests break results down by topic immediately, so a weak spot in one specific test doesn't stay hidden inside an otherwise decent overall score.
Getting your CLP before the skills test
Passing the required written tests gets you a Commercial Learner's Permit (CLP), which costs $44 in Missouri — a $25 written exam fee, $10 permit transaction fee, and $9 office processing fee.
Federal rule then requires holding the CLP for a minimum period and completing entry-level driver training (ELDT) before the skills test.
Frequently Asked Questions
How many questions are on Missouri's CDL General Knowledge test?
About 50 questions, the federally standard length used nationwide, not a Missouri-specific number.
Do I need the Air Brakes and Combination Vehicles tests too?
Only if you're training on equipment with air brakes or a combination vehicle — otherwise the General Knowledge test alone may suffice, depending on your license class.
What does the Missouri CLP cost?
$44 total: a $25 written exam fee, $10 permit transaction fee, and $9 office processing fee.
Ready to put this into practice?
Start a free Missouri cdl practice testLast reviewed: 2026-07-21