Two questions come up more than any others before a CDL test: how many questions is it, and what do I need to pass.
The honest answer is that both are set by your state, not federally. But the range is narrow enough to plan around, and the structure is the same everywhere.
Why it varies
The CDL is a federal framework administered by the states. The FMCSA sets what must be covered and the minimum standards; each state writes and administers its own exams within that.
So the topics are consistent nationwide — the same manual chapters, the same rules — while the question count, passing threshold, fees and retake policies are local.
This is also why a practice app helps with the material but cannot tell you your state's exact pass mark. For that, the DMV page is the source.
The general shape
General Knowledge is the longest of the core written tests in most states, by a clear margin.
The endorsement tests are shorter — often substantially so. Air Brakes and Combination Vehicles sit in between.
Eighty percent is the most common passing requirement across states and tests. Some set it higher for particular exams. Very few set it lower.
The practical consequence of an eighty percent line is that you have limited room. On a short endorsement test, a handful of wrong answers is the whole margin.
Aim well above the line
Treat ninety percent in practice as your target, not eighty. Test-day conditions — an unfamiliar screen, time pressure, nerves — reliably cost people a few points. A practice score sitting exactly on the pass mark is a coin flip.
If you fail
States handle retakes differently, and the variables are worth knowing before you sit down.
Waiting period. Some states let you retake the same day. Others impose a wait of a day or more.
Fees. Some include a number of attempts in the original fee. Others charge each time.
Attempt limits. Some cap attempts within a period, after which you re-apply from the start.
Failing one test does not invalidate the others. If you pass General Knowledge and fail Air Brakes, you generally keep the pass and re-sit only the failure.
Reading your own score
A single overall percentage hides the thing you most need to know.
Eighty-two percent could mean you are evenly borderline across every topic, or strong on six sections and badly weak on one. Those two situations call for completely different evenings of study.
Practise in a way that shows the breakdown by section, and target the gap. Repeating a full mixed test over and over mostly re-tests what you already know.
What a passing score does not tell you
Passing at exactly the threshold and passing comfortably are the same result on paper and very different in the vehicle.
The written tests exist because the material keeps people alive. A driver who scraped through on brake failure questions has a licence and a gap, and the gap shows up on a downgrade rather than in an exam room.
This is worth saying plainly because a lot of preparation advice treats the pass mark as the target. It is the floor.
Fees and what they cover
Costs vary widely by state and are worth knowing before you plan.
Typical components: an application fee, a fee per written test or a bundled fee covering several, a skills test fee, and the licence issuance fee itself. Endorsements often carry their own charges, and HAZMAT adds the federal background check fee on top.
Some states include a set number of retakes in the original fee. Others charge full price each attempt. That single difference changes how conservative you should be about booking before you are ready.
The DOT physical is a separate cost, paid to the medical examiner rather than the state, and is not usually covered by any of the above.
Booking at the right moment
The practical question is not what score passes but when to book.
A reasonable rule: book when your weakest section has been consistently comfortable for several sessions, not when your average first touches the pass mark. Averages hide the section that will fail you.
If your state charges per attempt, add a margin. If retakes are free and same-day, you can afford to be more aggressive. Let the local rules set your risk tolerance rather than a general principle.
Quick answers
What is the passing score for the CDL written test?
Eighty percent in most states, but it is set locally and can differ between exams. Check your state DMV page.
How many questions is the General Knowledge test?
It is the longest core test in most states. The exact number is set by the state, so confirm it rather than relying on a figure quoted for somewhere else.
Can I retake just the test I failed?
Generally yes. Passes on other exams normally stand, and you re-sit only what you failed — subject to your state's waiting and fee rules.
How many times can I retake it?
That is state-specific. Some allow unlimited attempts with a fee each time; others cap attempts in a period. Ask at the DMV before you book.
Where to get it
CDL Prep Exam 2026: Permit scores you per module so you can see which sections are actually weak. Offline, free to start.
Get your state's exact numbers from the DMV, then practise until you are clear of them by a margin.