The federal Commercial Driver's License regulations require a minimum passing score of eighty percent on every CDL knowledge exam, in every state, for every endorsement. The figure is set by 49 CFR Part 383 and is binding on state licensing agencies; no state can lower the threshold and remain in compliance with federal CDL standards.
What "eighty percent" actually looks like
On a fifty-question General Knowledge exam, eighty percent means forty correct. Miss eleven questions and you fail. On a twenty-five-question endorsement exam, the threshold is twenty correct — five wrong is the limit. The math is unforgiving precisely because federal regulators want it to be: a CDL applicant who cannot consistently identify the correct safe-operating procedure on multiple-choice questions has not yet demonstrated the baseline knowledge required to operate a commercial vehicle.
How scores are reported
Most states report your score immediately on completion of the test, either as a percentage or as a number-correct figure. Some states issue a printed score sheet; others report verbally at the counter. If you fail, your score is logged in the state record and you are typically required to wait at least one business day before retesting.
What "passing" does not mean
A passing score on the knowledge test does not authorize you to drive a commercial vehicle. It only qualifies you to take the skills test in a vehicle representative of the class of CDL you are seeking. The skills test is a pass-fail evaluation of pre-trip inspection, basic vehicle control, and on-road driving — and it has its own substantial failure rate.
For drivers preparing for What Is a Passing Score on the CDL Knowledge Test?, 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.