California CDL Written Test
Last updated: September 2026
What is the California CDL written test?
It's a set of computer-based knowledge tests. General Knowledge has 50 questions, Air Brakes 25, and Combination Vehicles 20. Each requires 80% to pass, and you get 3 attempts per test.
Source: California Commercial Driver Handbook (DL-650)
What the California CDL Written Test Is
The written test (also called the knowledge test or permit test) is the first step toward a California Commercial Driver's License. Passing it earns your Commercial Learner's Permit (CLP). The questions are drawn from the California Commercial Driver Handbook (DL-650).
After you hold your CLP for 14 days, you can take the skills test. Entry-Level Driver Training (ELDT) is required before the skills test (FMCSA).
Knowledge Tests You May Need
| Test | Questions | Passing Score |
|---|---|---|
| General Knowledge | 50 | 80% (40 correct) |
| Air Brakes | 25 | 80% (20 correct) |
| Combination Vehicles | 20 | 80% (16 correct) |
Passing Score
Each knowledge test requires a passing score of 80%. For General Knowledge, that's 40 of 50 correct; for Air Brakes, 20 of 25; for Combination Vehicles, 16 of 20.
How Many Attempts
You have three attempts to pass each knowledge test. If you fail the same test three times, your application is no longer valid and you must reapply. Check with the California DMV for current retesting requirements.
How to Prepare
- Study the California Commercial Driver Handbook (DL-650).
- Understand which tests apply to your CDL class.
- Review the high-yield numbers — start with the air brake PSI numbers.
- Practice the concepts, not just memorized answers.
Requirements Before You Test
You'll take the written test at a California DMV office. Check the California DMV website for current application and documentation requirements.
Related Resources
Frequently Asked Questions
How many questions are on the California CDL written test?+
General Knowledge has 50 questions, Air Brakes has 25, and Combination Vehicles has 20. Each requires 80% to pass.
What score do you need to pass the California CDL test?+
80% on each knowledge test. For General Knowledge, that's 40 of 50 correct.
How many times can you take the California CDL written test?+
Three attempts per knowledge test. After three failed attempts, your application is no longer valid and you must reapply.
Is the California CDL written test the same as the permit test?+
Yes. The written test is also called the knowledge test or permit test. Passing it earns your Commercial Learner's Permit (CLP).
What tests do I need for a Class A CDL in California?+
All applicants take General Knowledge. Class A applicants also take Combination Vehicles. If your vehicle has air brakes, you take the Air Brakes test too. Endorsement tests are separate.
This page is an independent study resource. It is not affiliated with the California DMV. Verify current requirements against official sources.