CDL test score calculator
You pass each CDL knowledge test with 80% of its questions right.
of 50
Your score
You need 40 of 50 to pass
Check yourself on a free practice test
Free practice questions with the reason for every answer, no account. You see your weakest topic and get a short lesson on it.
CDL passing score by test length
| Questions | Right to pass | You can miss |
|---|---|---|
| 20 | 16 | 4 |
| 25 | 20 | 5 |
| 30 | 24 | 6 |
| 40 | 32 | 8 |
| 50 | 40 | 10 |
Questions people ask
What is the passing score for the CDL knowledge test?
80% on each knowledge test. It is a federal rule that every state applies.
How many questions can you miss on the CDL general knowledge test?
One in five. States set the number of questions; on a 50-question test you can miss 10 and need 40 right.
What happens if I fail the air brakes test?
You can still be issued a CLP or CDL, but it carries an air brake restriction.
What happens if I fail the combination vehicles test?
You cannot be issued a Group A CLP or CDL without a pass.