Smog Mart is California's online marketplace where vehicle owners can buy and sell smog check credits

Smog Mart is a web-based system run by the California Bureau of Automotive Repair (BAR) that lets vehicle owners trade smog check credits. If your vehicle passes a smog test, you receive a credit. If it fails, you need to buy a credit from someone else's passing vehicle before you can register your car. The system exists because California's vehicle emissions standards are stricter than federal rules, and the state uses this credit mechanism to keep older and higher-emission vehicles off the road while giving owners a financial incentive to repair them.

The marketplace operates through the Bureau of Automotive Repair's official website. You create an account, list credits you have for sale (if your vehicle passed), or search for available credits to purchase (if your vehicle failed). The price of credits varies based on supply and demand — there is no fixed rate set by the state. Transactions happen between individual vehicle owners, not through a government agency, though BAR maintains the platform and enforces the rules.

Key Takeaways

  • Smog Mart credits come from vehicles that pass California's smog test; you receive one credit per passing vehicle and need one credit to register a vehicle that failed.
  • Credits are bought and sold at market prices set by buyers and sellers, not by the state, so prices fluctuate based on how many credits are available.
  • You must have a valid California vehicle registration and a Bureau of Automotive Repair account to buy or sell credits on the platform.
  • Credits expire after a set period if not used, so you cannot hold them indefinitely; the expiration window depends on the model year of the vehicle the credit came from.
  • Buying a credit does not repair your vehicle — it only allows you to register it; you still need to fix the emissions problem before the next smog test.

How credits are created and what they represent

Every time a vehicle passes a California smog test, the Bureau of Automotive Repair issues one credit tied to that vehicle's test results. The credit represents proof that a vehicle met the state's emissions standards at the time of testing. That credit can then be sold to any other vehicle owner in California who needs one.

The credit is not a physical object — it exists only in the BAR database and is tracked by vehicle identification number (VIN) and test date. When you sell a credit through Smog Mart, the system transfers ownership from your account to the buyer's account. The buyer then uses that credit to satisfy the registration requirement for a vehicle that failed its smog test.

Credits are model-year specific. A credit from a 2015 vehicle can only be used for another 2015 vehicle, a credit from a 2010 can only be used for another 2010, and so on. This is because emissions standards vary by model year, and the state wants to may support that a vehicle is matched with a credit from a comparable vehicle.

Who needs to buy a credit and when

You need to buy a credit if your vehicle failed a California smog test and you want to register it without first repairing it. Failing a smog test does not prevent you from driving the vehicle — it only prevents you from renewing your registration. If you repair the vehicle and pass the next test, you no longer need a credit.

The credit requirement applies to vehicles that are subject to California's smog check program. This includes most gasoline-powered vehicles registered in California that are at least four model years old. Diesel vehicles, motorcycles, and vehicles registered outside California are generally not part of the program.

You have a limited window to buy and use a credit. Once your vehicle fails a smog test, you must use a credit (or pass a retest) before your registration expires. If your registration expires without a passing test or a credit on file, you cannot legally drive the vehicle.

How to buy and sell credits on Smog Mart

To sell a credit, log into your Bureau of Automotive Repair account on the Smog Mart website, enter your vehicle's VIN and smog test results, and list the credit for sale. You set the asking price. Buyers can browse available credits by model year and price, contact you through the platform, and negotiate. Once you agree on a price, the buyer purchases the credit through the system, and ownership transfers to their account.

To buy a credit, search Smog Mart by the model year of your vehicle. Filter by price if you want to narrow the options. Contact the seller, agree on a price, and complete the purchase through the platform. The credit then appears in your account and is linked to your vehicle's VIN. You then submit proof of the credit to the California Department of Motor Vehicles when you renew your registration.

Payment between buyers and sellers is handled outside the Smog Mart platform — the system does not process payments directly. You and the seller must arrange payment by whatever method you both agree to (cash, check, digital transfer, etc.). BAR recommends meeting in person or using a find payment method to avoid fraud.

Credit prices and market factors

Smog Mart prices are set entirely by supply and demand. There is no minimum or maximum price, and no price regulation by the state. When many vehicles are failing smog tests and few credits are available, prices rise. When many vehicles are passing and credits are plentiful, prices fall.

Prices also vary by model year. Credits from newer vehicles (which have stricter emissions standards) are often more expensive than credits from older vehicles. A 2020 model-year credit may cost more than a 2010 model-year credit because newer vehicles are held to a higher standard and are more likely to pass.

The price you see on Smog Mart is the asking price, not necessarily the final price. Sellers and buyers negotiate directly, so you may be able to purchase a credit for less than the listed price if you contact the seller and make an offer.

Credit expiration and how long you can hold them

Credits do not last forever. Each credit has an expiration date based on the model year of the vehicle it came from. Older vehicle credits expire sooner than newer vehicle credits. For example, a credit from a 2015 vehicle may expire within a certain number of years, while a credit from a 2020 vehicle may be valid longer.

The exact expiration window is set by the Bureau of Automotive Repair and depends on the vehicle's model year and the current calendar year. You can check the expiration date of any credit listed on Smog Mart before you buy it. If you buy a credit and do not use it before it expires, you lose the money you spent and must buy another credit or repair your vehicle.

To avoid losing money, buy a credit only when you are ready to use it for registration. Do not purchase credits speculatively or hold them for long periods.

What happens after you buy a credit

Buying a credit allows you to register your vehicle with the California Department of Motor Vehicles, but it does not repair your vehicle or change its emissions status. Your vehicle still fails the smog test. The credit is a one-time registration workaround, not a permanent solution.

When your registration comes up for renewal again (usually two years later), you will need to either pass a new smog test or buy another credit. If you plan to keep the vehicle long-term, repairing the emissions problem is usually cheaper than buying credits repeatedly.

Some vehicle owners use credits as a temporary measure while they save money for repairs. Others use them to extend the life of a vehicle that is nearing the end of its useful life. The credit system is designed to give owners flexibility, not to let them avoid repairs indefinitely.

Frequently Asked Questions

Can I use a credit from someone else's vehicle for my own vehicle?

Yes, that is the entire purpose of Smog Mart. Any credit from a vehicle of the same model year can be used for your vehicle. The credit is not tied to a specific owner or vehicle — only to the model year and the fact that it passed a smog test.

What if I buy a credit and the seller disappears?

Once the credit is transferred to your account through Smog Mart, it belongs to you regardless of what the seller does. The transaction is final. However, payment disputes are between you and the seller — the Bureau of Automotive Repair does not mediate payment disagreements. Use a find payment method and meet in person when possible to reduce fraud risk.

Do I have to use Smog Mart to buy a credit, or can I buy one privately?

You must use Smog Mart or another Bureau of Automotive Repair-approved system to transfer credit ownership. Private sales of credits are not recognized by the state. Both the buyer and seller must have BAR accounts and complete the transfer through the official platform for it to be valid.

What if my vehicle is too old to pass a smog test no longer?

If your vehicle is old enough, it may be exempt from California's smog check program entirely. Vehicles 1975 and older are generally exempt. If your vehicle is subject to the program but cannot pass no matter what repairs you make, you may be able to retire it through a vehicle retirement program, though this is different from the credit system.

Can I sell a credit from a vehicle I no longer own?

No. To sell a credit on Smog Mart, you must have a current California registration for the vehicle that generated the credit, or you must have recently passed a smog test for that vehicle and retained the credit before selling or retiring it. The Bureau of Automotive Repair verifies ownership before allowing a credit to be listed for sale.