One of the most common questions we get from new applicants is, "How many questions are on the CDL knowledge test?" The honest answer is that the question count is not fixed by federal regulation — each state pulls its live exam from the federal pool of approved questions independently — but the typical counts are well-documented and consistent enough that we can give you a reliable expectation.
The expected counts, by exam
The General Knowledge exam is universally fifty multiple-choice questions across all U.S. states. Air Brakes runs twenty-five questions in most jurisdictions. Combination Vehicles is also typically twenty-five. Hazmat runs thirty questions; Tanker, Doubles/Triples, Passenger, and School Bus are typically twenty to twenty-five questions each.
The passing score is set by federal regulation at eighty percent. That means you need at least forty correct on General Knowledge, twenty correct on a twenty-five-question endorsement exam, and twenty-four correct on a thirty-question Hazmat exam. The threshold is not negotiable — states cannot lower it.
Why state counts vary
States can and do vary the exact number of questions delivered for each subject area. A few jurisdictions deliver a longer General Knowledge exam (sixty or even seventy questions) when they want a broader sample of the candidate's knowledge. A few use shorter endorsement exams (twenty questions instead of twenty-five). The variation is small, but if you want the exact count, the only authoritative source is your state CDL Manual.
Practical study advice
Plan your practice volume to be roughly five to ten times the live exam length. For General Knowledge, that means working through two hundred fifty to five hundred practice questions over your study period. For each endorsement, plan on at least one hundred to two hundred practice questions. The diminishing-returns point sets in around the five-hundred-question mark for General Knowledge — past that, additional practice mostly stress-tests fatigue rather than knowledge.
For drivers preparing for How Many Questions Are on the CDL Test? (Every Section, 2026), additional context — including federal manual excerpts, employer hiring practices, and DOT medical guidance — is widely available from industry resources. Continue reading on a recommended industry resource for further detail. Always cross-check anything you read with the current edition of your state CDL manual, since enforcement guidance is updated periodically.