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Checked Oct 7, 2026

CDL test facts for 2026

General Knowledge has 50 questions and you need 40 right. Every knowledge test needs 80%. Here is the full table, with a source for each line.

Written test formats

National defaults. A few states use different question counts or time limits, so each state page lists its own numbers when we have them.

TestQuestionsTo passTypical timeSources
General Knowledge5040 (80%)About 60 minutesMassachusetts CDL Manual, 49 CFR 383.135, passing knowledge and skills tests
Air Brakes2520 (80%)25 to 30 minutesMassachusetts CDL Manual, 49 CFR 383.135, passing knowledge and skills tests
Combination Vehicles20 (25 questions in some states)16 (80%)20 to 25 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format
Hazardous Materials3024 (80%)30 to 40 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format
Tanker2016 (80%)20 to 25 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format
Passenger2016 (80%)20 to 25 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format
School Bus20 (25 questions in some states)16 (80%)About 25 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format
Doubles/Triples2016 (80%)About 20 minutesMassachusetts CDL Manual, Crist CDL: Ohio test format

The 80% passing score is a federal minimum. Question counts and time limits are set by each state, and these are the national defaults we use for the timed tests on this site.

Federal rules that apply everywhere

RuleSource
Passing score: at least 80% of the questions on each general and endorsement knowledge test.49 CFR 383.135
Minimum age: 18 to apply for a CDL and drive within your state. 21 to drive across state lines.49 CFR 383.71 and 391.11
A CLP holder must wait 14 days after the CLP is first issued before taking the skills test.49 CFR 383.25
Entry-level driver training applies to people who get a CLP on or after February 7, 2022, for first-time Class A or B, and first-time S, P or H. The provider must be on the Training Provider Registry.FMCSA Training Provider Registry
Hazmat endorsement needs a TSA security threat assessment with fingerprints.TSA hazmat endorsement
The School Bus endorsement requires passing the Passenger knowledge test as well.49 CFR 383.123
Endorsement letters: H hazmat, N tank vehicle, P passenger, S school bus, T doubles and triples, X tank plus hazmat.49 CFR 383.93
Buses carrying passengers and vehicles carrying certain hazardous materials must stop 15 to 50 feet from the nearest rail at a railroad crossing.49 CFR 392.10

State pages

Common questions

How many questions are on each CDL written test?

General Knowledge 50, Air Brakes 25, Combination Vehicles 20 (25 in some states), Hazmat 30, Tanker 20, Passenger 20, School Bus 20 (25 in some states) and Doubles/Triples 20. These are national defaults.

What is the passing score for the CDL written test?

80% on each knowledge test. That is the federal minimum in 49 CFR 383.135, and states may not go lower.

Do all states use the same CDL test?

The topics come from a national model manual, so they are very similar. Question counts for a few tests, time limits and some rules differ by state.

How often is this table updated?

We check the formats against official sources and state manuals and show the date at the top of the page. State pages are added as we verify each state.