How Old Must a Car Be to Be Smog Exempt in California?

In California, a gasoline-powered car is permanently exempt from smog checks if its model year is 1975 or older, and it’s exempt from the regular biennial smog inspection if it’s eight model years old or newer. Diesel vehicles follow a different rule: any diesel with a model year of 1997 or earlier is exempt, but newer diesels get no age-based grace period. Battery-electric vehicles and motorcycles are exempt outright, regardless of age.¹

Gasoline Vehicles: The 1975 Cutoff

Any gasoline, hybrid, or alternative-fuel vehicle built before the 1976 model year is permanently exempt from California’s smog check program.² The exemption sticks with the vehicle regardless of how many times it changes hands or where in the state it’s registered. The DMV recognizes it automatically from the model year on the title, so there’s no application and no paperwork.

California picked a fixed 1975 line rather than a rolling one, which means the pool of exempt cars shrinks over time as these vehicles come off the road. The cutoff reflects the era before modern emissions controls became standard equipment.

One caveat: being exempt from testing doesn’t mean the original emissions equipment can come off. Removing a catalytic converter or disabling factory controls can still create legal problems on a car old enough to skip smog checks.

The Eight-Year Rule for Newer Vehicles

At the other end of the age scale, gasoline, hybrid, and alternative-fuel vehicles that are eight model years old or newer don’t need biennial smog inspections when renewing registration.¹ The reasoning is that a newer vehicle with an intact factory emissions system is unlikely to have developed problems severe enough to fail.

In place of the inspection, owners pay an annual smog abatement fee at registration renewal, typically $20 to $25 depending on the vehicle’s age. Once the vehicle is past its eighth model year, that fee drops off and the every-other-year smog check kicks in. A 2020 model, for instance, would be due for its first biennial check when it reaches model year nine, which puts the first test in 2028 at the earliest.²

This grace period covers biennial renewal only. Certain other events, covered below, can still trigger a smog check on a nearly new car.

Diesel Vehicles Follow Different Ages

Diesel age rules don’t mirror the gasoline rules, so it’s worth reading them on their own terms.

A diesel car or truck with a model year of 1997 or earlier is exempt from smog checks.¹
There is no eight-year newer-vehicle exemption for diesels. A 1998 or newer diesel that falls within the program needs biennial checks no matter how new it is.
Diesels with a gross vehicle weight rating above 14,000 pounds are exempt from the standard smog check program, regardless of model year.¹

Vehicles Exempt Regardless of Age

Some vehicles never need a smog check, whatever the model year.

Battery-electric vehicles are fully exempt because they produce no tailpipe emissions. No smog check, no abatement fee, ever. Motorcycles are also exempt across the board; the statute authorizes future motorcycle testing, but the state has not implemented it.²

Plug-in hybrids are a common point of confusion. They are not treated as electric vehicles for smog check purposes. Because a plug-in hybrid still has a gasoline engine, it follows the same rules as any other hybrid and is subject to smog checks once it ages past the eight-year window.

When Age Won’t Save You From a Smog Check

An age-based exemption from the biennial cycle doesn’t cover every situation. A few events can require a smog check on a vehicle that would otherwise be exempt from routine testing.

Registering a vehicle in California for the first time triggers a smog check regardless of how new the vehicle is. That covers moving to California from another state, or buying a car out of state and bringing it in. Specially constructed vehicles being registered for the first time also require a smog check.¹²

Selling a vehicle brings its own rules. The seller in a private-party sale generally has to provide a smog certificate from an inspection performed within the previous 90 days.³ Vehicles four model years old or newer are the exception: no smog check for the change of ownership, and the buyer pays an $8 smog transfer fee to the DMV at title transfer.⁴ Transfers between immediate family (spouse, domestic partner, sibling, child, parent, grandparent, grandchild) don’t require a smog certificate either, with one wrinkle: if a family member bought the car for you but titled it in their name first, a smog check is required before it transfers to you. And a vehicle exempt by age or type (1975-or-older gas, 1997-or-older diesel, fully electric, motorcycle) needs no smog check for a sale.

Finally, the state can flag a vehicle as “directed,” meaning the smog check must be done at a STAR-certified station. The Bureau of Automotive Repair uses a statistical model to identify vehicles more likely to fail, plus a small random sample for program evaluation.⁵ Your registration renewal notice will say if this applies. Direction is triggered by the vehicle’s profile, not its age, so a car in the biennial testing pool can be directed no matter where it sits on the age spectrum.

1
California Bureau of Automotive Repair. Smog Check: When You Need One and What’s Required
2
California Legislative Information. California Code, Health and Safety Code HSC 44011
3
California DMV. Smog Inspections
4
California Legislative Information. California Code, Vehicle Code VEH 4000.1
5
California Bureau of Automotive Repair. Smog Check Reference Guide 2025