California smog tests are required every two years for most vehicles, with some exceptions based on age and type

In California, your vehicle needs a smog test every two years if it is registered in the state. The test must happen before your registration expires. If your vehicle was first registered in California less than six years ago, you may be exempt from testing in the first four years — but you still need one before the six-year mark. Vehicles that are eight years old or older must be tested every two years without exception.

The exact timing depends on when your vehicle was first registered and what your registration expiration date is. Your registration renewal notice will tell you whether a smog test is required that year. If the notice says "smog test required," you must complete it before you renew your registration with the Department of Motor Vehicles (DMV).

Key Takeaways

  • Most California vehicles need a smog test every two years, timed to your registration renewal date.
  • New vehicles (less than six years old) may skip testing for the first four years, but must be tested before the six-year anniversary.
  • Vehicles eight years old and older have no exemption and must test every two years.
  • Your registration renewal notice will state whether a smog test is required that year.
  • You cannot renew your registration without a passing smog test result if one is required.

When your vehicle's age determines the testing schedule

California's smog test requirement is tied to your vehicle's model year, not how long you have owned it. A vehicle that is brand new when you buy it will not need a smog test for four years. After that four-year window, testing becomes mandatory every two years.

Once your vehicle reaches eight years old, there are no more exemptions. An eight-year-old vehicle must be tested every two years for the rest of its life on California roads, regardless of condition or mileage. This applies whether the vehicle is a sedan, truck, motorcycle, or SUV.

Diesel vehicles follow the same two-year cycle as gasoline vehicles once they are old enough to require testing. However, diesel trucks and some commercial vehicles may have different testing requirements — check your renewal notice or contact the DMV if you drive a commercial or specialty vehicle.

How registration expiration dates control your test timing

Your smog test must be completed within a specific window before your registration expires. California allows you to take the test up to 90 days before your registration renewal date. You cannot test earlier than that window — a test taken more than 90 days before expiration will not count toward your renewal.

Once you pass the smog test, you have a valid test result for 30 days. This means you should schedule your test no later than 60 days before your registration expires, to give yourself time to renew the registration before it lapses. If your test result expires before you renew, you will need to test again.

If your registration has already expired and you did not renew it, you cannot legally drive the vehicle. You will need to renew the registration and provide a current smog test result. The DMV will not accept a test result that was taken before the vehicle's registration expired.

Vehicles and situations that do not require smog testing

Certain vehicles are permanently exempt from California smog testing. These include vehicles that are less than four years old (on their first registration cycle), electric vehicles, and vehicles registered as classic cars or street rods under specific DMV programs. Motorcycles registered in California do require smog tests, but only every two years like other vehicles.

Vehicles registered outside California but driven in the state temporarily do not need California smog tests. However, if you move to California and register your vehicle here, it will be subject to California's testing requirements from that point forward, regardless of its age.

If your vehicle fails a smog test, you have 30 days to repair it and retest at no additional cost at the same testing station. Some repairs may be covered under California's Smog Check Repair information Program if your household income is below a certain threshold, though this program has limited funding and is not always available.

What happens if you miss your smog test important date

If your registration expires and you have not completed a required smog test, your registration becomes invalid. You cannot legally drive the vehicle until you renew the registration, which requires a current smog test result. Driving with an expired registration can result in a traffic citation.

If you realize you need a smog test after your registration has expired, you can still get one and renew your registration. However, you will owe late fees to the DMV in addition to the registration renewal cost. The longer the registration remains expired, the higher the late fees become.

Some people choose to renew their registration online through the DMV website, but if a smog test is required, you cannot complete the online renewal without a test result. You must visit a smog testing station first, then return to the DMV website or visit a DMV office to finish the renewal.

Finding a smog testing station and understanding test results

California has thousands of smog testing stations licensed by the Bureau of Automotive Repair (BAR). You can find a station near you through the BAR's online station locator or by searching for "smog test" in your area. Prices vary by station but typically range between $30 and $80 for a basic smog test.

When you arrive at a testing station, bring your vehicle registration and proof of ownership. The technician will run your vehicle through an emissions test, which usually takes 15 to 30 minutes. You will receive a test result on the spot — either a pass, fail, or conditional pass.

A passing result is valid for 30 days and can be submitted to the DMV to renew your registration. If you fail, you have 30 days to repair your vehicle and retest at the same station for free. A conditional pass means your vehicle barely passed and you should monitor it for emissions issues, but you can still renew your registration.

Frequently Asked Questions

Can I take my smog test more than 90 days before my registration expires?

No. California only accepts smog test results taken within 90 days of your registration expiration date. A test taken earlier will not count, and you will need to test again closer to your renewal date. Plan your test for 60 to 90 days before expiration to stay within the window.

What if I just bought a used car and do not know when it needs a smog test?

Check the registration renewal notice that came with the vehicle, or contact the DMV with your vehicle identification number (VIN). The DMV can tell you the exact expiration date and whether a smog test is required. You can also check online through the DMV website if you have your registration number.

Do I have to test at a specific smog station, or can I go anywhere?

You can use any Bureau of Automotive Repair-licensed smog testing station in California. If you fail a test, you must retest at the same station within 30 days at no charge. After that 30-day window, you can test at a different station if you choose.

What if my vehicle is registered in another state but I live in California?

If you live in California, you must register your vehicle in California within a certain time period. Once registered in California, your vehicle will be subject to California smog testing requirements. If your vehicle is still registered out of state, you are not required to take a California smog test, but you cannot legally register it here without one.

Can I renew my registration online if I need a smog test?

No. If a smog test is required, you must complete it first and receive a passing result. Then you can renew your registration online through the DMV website, by mail, or in person at a DMV office. The test result must be current (within 30 days of the renewal date).