Smog check costs vary by state and test type, but most inspections run between $30 and $80

A basic smog check—the kind most states require every two years or when you buy a used car—costs somewhere between $30 and $80 at a certified testing station. California, which runs the strictest emissions program in the country, typically charges $30 to $50 for a standard test on a vehicle made after 1975. Older vehicles, diesel engines, and hybrid or electric cars may cost more or require different testing altogether. The exact price depends on your state's program, your vehicle's age and type, and which testing station you choose.

The fee you pay covers the actual test—the machine that reads your vehicle's emissions data—plus the station's labor and the certificate they issue if you pass. If you fail, most states charge a retest fee, which is usually $10 to $25 and happens after you've had repairs done. Some stations bundle the first test and retest into one price; others charge separately. Always ask the station upfront whether the quoted price includes both the test and the certificate, or whether there are additional fees.

Key Takeaways

  • Standard smog checks cost $30 to $80 depending on your state, vehicle age, and engine type.
  • Retests after repairs typically cost $10 to $25 extra, though some stations offer package pricing.
  • California, New York, and a handful of other states require regular smog checks; many states do not.
  • Certified testing stations are the only legal option; prices are set by individual stations, not by the state.
  • Failing a smog check usually means repairs will cost far more than the test itself—often $200 to $1,000 or more.

Why prices differ between stations and states

Your state's environmental agency sets the rules for what gets tested and how, but individual certified stations set their own prices. Two stations in the same city may charge $35 and $65 for the same test. There is no state-mandated price cap in most places, so shopping around can save you $20 to $30. Call ahead or check online reviews to find stations near you and compare their quoted prices.

States with stricter emissions standards—California, New York, Massachusetts, and Vermont—tend to have more expensive tests because the equipment is more sophisticated and the testing protocol is longer. California's two-speed idle test, which measures emissions at both low and high engine speeds, takes longer than a straightforward plug-in diagnostic and costs more. Newer vehicles with onboard diagnostic systems may may have access to for a cheaper "OBD test" that just reads the computer, while older cars need a more involved tailpipe test.

What happens if you fail and need repairs

Failing a smog check does not cost you anything extra at the testing station—the retest fee is usually $10 to $25—but the repairs needed to pass will cost significantly more. Common failures include a faulty oxygen sensor ($150 to $300), a bad catalytic converter ($400 to $1,200), or a malfunctioning emissions control system ($200 to $800). If your check engine light is on, that alone will cause a failure in most states, and diagnosing the underlying problem can run $100 to $200 before you even start repairs.

Some states offer repair information programs or waivers for low-income vehicle owners who cannot afford to fix emissions problems. California's Smog Check Repair information Program, for example, can help pay for repairs up to a certain amount if your household income is below a threshold. Check your state's environmental agency website to see whether you may have access to. If repairs cost more than your vehicle is worth, you may be may be able to access for a vehicle replacement or retirement program instead.

Testing requirements by state

Not every state requires smog checks. California, New York, Massachusetts, Vermont, Maine, and Connecticut have mandatory emissions testing programs. Some states test only in certain counties or only for vehicles above a certain age. Texas, for instance, requires testing only in areas that do not meet federal air quality standards, so a vehicle in Houston may need a test while one in rural West Texas does not.

Your vehicle registration documents or your state's Department of Motor Vehicles website will tell you whether you need a test and how often. If you are buying a used car, the seller's state determines whether a pre-sale test is required, not your state. A car bought in California must pass a smog check before the title transfers, even if you are moving it to a state with no testing program. Once you register it in your home state, you follow that state's rules going forward.

How to find a certified testing station

Certified smog check stations are licensed by your state's environmental or motor vehicle agency. You cannot get a legal smog check at an independent repair shop unless it is also certified. Your state's DMV or environmental agency website has a searchable list of certified stations, usually organized by county or zip code. California's Bureau of Automotive Repair maintains an online directory; New York's Department of Environmental Conservation does the same.

When you call or visit a station, confirm that they are certified for your vehicle type—some stations test only gasoline vehicles, while others handle diesel or hybrids. Ask whether they offer same-day results or whether you need to wait for lab processing. Most stations can print your passing certificate on the spot, but a few send results electronically to the state, which can take a few days. If you are on a tight timeline before your registration expires, ask about turnaround time before you book.

What to bring and how to prepare

Bring your vehicle registration or proof of ownership and a valid photo ID. The testing station will need your vehicle identification number (VIN), which is on your registration and on the dashboard. Make sure your gas tank is at least half full—some tests require the fuel level to be above a certain point—and that your vehicle has been warmed up for at least 20 minutes before the test. A cold engine can fail emissions tests even if the vehicle is in good condition.

If your check engine light is on, the test will fail automatically in most states, regardless of what the emissions reading shows. Have that diagnosed and repaired before you go in for a test. If you have recently had work done on your emissions system, drive the vehicle for at least 50 to 100 miles before testing so the computer can recalibrate. Skipping this step is one of the most common reasons for a failed retest.

Frequently Asked Questions

Can I get a smog check at any repair shop?

No. Only certified testing stations licensed by your state can perform a legal smog check. An independent repair shop can diagnose and fix emissions problems, but the actual test must be done at a certified station. Your state's DMV or environmental agency website has a list of certified locations.

What if I fail the smog check—do I have to pay to retest?

Yes, retests usually cost $10 to $25, though some stations include one free retest with the initial test fee. After you have repairs done, you can return to the same station or go to a different certified station for the retest. You have a set window—usually 30 days—to retest before you have to start over.

Do I need a smog check if I just bought a used car?

It depends on your state and where you bought the car. If you bought it in a state that requires pre-sale testing, the seller must have had it tested before the sale. Once you register it in your home state, you follow that state's testing schedule. Check your state's DMV website for the specific rules.

How long does a smog check take?

Most tests take 15 to 30 minutes from start to finish. Some stations have a wait, especially during peak times like the end of the month. Call ahead to ask about wait times, or check whether the station takes appointments. If you fail and need repairs, the retest can happen the same day if repairs are quick, or days or weeks later depending on what needs fixing.

What if my vehicle is too old to test?

Most states exempt vehicles older than 30 to 35 years, depending on the state. California exempts vehicles made before 1975. Check your state's rules, as the cutoff varies. If your vehicle is exempt, you still need to register it, but you do not need a smog check. Your registration documents will note whether testing is required.