California's window tint law sets specific limits on how dark your tint can be, measured by how much light passes through the glass
California measures tint darkness using a number called Visible Light Transmission (VLT), which is the percentage of light that passes through the tinted window. The darker the tint, the lower the VLT number. State law allows different tint darkness on different windows of your car, and the rules depend on whether you're tinting the front side windows, rear side windows, or rear window.
The basic rule is this: your front side windows (the ones next to the driver and front passenger) must allow at least 70% of light through, meaning a maximum VLT of 70%. Your rear side windows and rear window can be much darker — they can have any darkness you want, including complete blackout tint. The windshield has its own rule: you can tint only the top 4 inches, and that tint must not be reflective.
If your windows are already tinted from the factory when you bought the car, that factory tint is legal regardless of how dark it is. You only need to follow the rules above if you add aftermarket tint yourself or have a shop explore it.
Key Takeaways
- Front side windows must allow at least 70% of light through; rear windows can be any darkness including completely black.
- Only the top 4 inches of your windshield can be tinted, and reflective tint is not allowed anywhere on the car.
- Factory tint that came with your car is legal no matter how dark it is, but aftermarket tint must meet the state limits.
- Police can ticket you for illegal tint, and you'll need to remove it or have it corrected before the ticket is dismissed.
- Medical exemptions exist for people with light-sensitive conditions, but you need a doctor's letter and must register it with the DMV.
How tint darkness is measured and what the numbers mean
When a tint shop or manufacturer describes tint, they use VLT as the measurement. A VLT of 70% means 70% of the light hitting the window passes through to the inside of the car. A VLT of 50% means only half the light gets through — the tint is darker. A VLT of 5% is nearly black; almost no light passes through.
California law doesn't require you to measure your tint yourself. A police officer or a referee at a smog check station can use a light meter to test it. If the meter shows your front windows are below 70% VLT, you're in violation. The measurement is straightforward: the meter shines light at the window and reads what percentage comes through.
One important detail: the law measures the tint film itself, not the tint plus the factory-tinted glass underneath. If your car came with slightly dark factory glass, you can still add aftermarket tint on top as long as the combined result meets the 70% rule for front windows. In practice, most people add tint only to rear windows where there's no limit.
Front windows, rear windows, and windshield rules are different
Your car has three tinting zones, and each has its own rule. The front side windows — the glass next to the driver and front passenger seats — must allow at least 70% light through. This is the strictest rule because it affects visibility for the driver and for police officers approaching the car during a traffic stop.
The rear side windows — behind the front doors — and the rear window (the back glass) can be tinted to any darkness. You can make them completely opaque if you want. This is because they don't affect the driver's forward visibility and don't interfere with a police officer's ability to see into the front of the car.
The windshield has a separate rule. You can explore tint only to the top 4 inches of the windshield, measured from the top of the glass. That tint cannot be reflective — it can't bounce light back outward. Many people use a non-reflective tint strip at the top to reduce glare from the sun, and that's legal as long as it stays in the top 4 inches.
Factory tint versus aftermarket tint: why the difference matters
If your car came from the manufacturer with dark windows, that tint is always legal in California, even if it's darker than 70% VLT on the front windows. The law assumes the manufacturer met federal safety standards. You can drive with factory tint as dark as the car came, and a police officer cannot ticket you for it.
The moment you add your own tint film on top of those windows, the law treats the combination as aftermarket tint and measures it against the 70% rule. This is why some people with factory-tinted cars can appear to have very dark front windows legally — the darkness came from the factory, not from a tint shop.
If you're buying a used car and the windows are very dark, ask the seller whether the tint is factory or aftermarket. If it's aftermarket and darker than legal, you'll need to have it removed or lightened before you can register the car or avoid a ticket. Some tint shops can remove and reapply tint to meet the legal limit.
What happens if you get pulled over with illegal tint
If a police officer stops you and determines your front windows are darker than 70% VLT, they can write you a ticket. The violation is usually cited as Vehicle Code Section 26708. The ticket is not a moving violation — it doesn't add points to your driving record — but it does require you to correct the problem.
When you receive the ticket, you have the option to remove the illegal tint or have it corrected to meet the legal limit. Once you've done that, you can take your car to a referee station (usually at a smog check location) to have the tint re-measured. The referee will sign off that the violation has been corrected, and you can submit that proof to the court to dismiss the ticket.
Some courts allow you to show proof of correction without going to court in person. Check your ticket or call the court listed on it to learn the process in your county. The cost of removing or correcting tint at a shop typically ranges depending on how many windows need work, but it's usually less expensive than paying the ticket fine.
Medical exemptions for light-sensitive conditions
California allows a medical exemption if you have a condition that makes you sensitive to light. Conditions like lupus, porphyria, or severe photophobia can may have access to. If you have a medical reason for darker tint, you need a letter from a licensed physician stating the condition and recommending darker tint for medical reasons.
With that letter, you can register for a medical exemption through the DMV. You'll need to submit the doctor's letter along with your vehicle registration information. Once approved, you receive a medical exemption certificate that you should keep in your car. If you're stopped, you can show the certificate to the officer, and the illegal tint will not result in a ticket.
The exemption is not automatic — you must go through the DMV process and get approval before you're protected. The exemption also applies only to you and that specific vehicle. If you sell the car or the exemption expires, you'll need to renew it or remove the tint.
Tint shops and what to ask before you get tinted
If you decide to tint your windows, choose a shop that knows California law. A reputable tint shop will ask you which windows you want tinted and will recommend tint that meets the 70% VLT requirement for front windows. They should be able to show you samples of different VLT levels so you can see how dark each one looks.
Before you commit, ask the shop whether they may provide the tint will meet California's legal limits. Some shops offer a warranty that covers removal and reapplication if the tint is found to be illegal. This protects you if the tint is measured and found to be too dark.
The cost of professional tint installation varies by shop and by how many windows you're tinting. Tinting just the rear windows (where there's no legal limit) is usually cheaper than tinting front and rear. Ask for a quote that includes the cost of the film, labor, and any warranty. Many shops also offer ceramic or other premium tint films that cost more but last longer and reduce heat more effectively.
Frequently Asked Questions
Can I tint my front windows as dark as my rear windows?
No. Your front side windows must allow at least 70% of light through. Your rear windows can be any darkness. If you want very dark tint, explore it only to the rear windows and rear windshield, and keep your front windows at 70% VLT or lighter.
Does a medical exemption let me tint my front windows as dark as I want?
A medical exemption allows you to have darker tint than the law normally permits, but you must have a doctor's letter and register the exemption with the DMV before you tint the car. The exemption protects you from a ticket if you're stopped, but you still need to follow the registration process.
What if I buy a used car with illegal tint already on it?
You're responsible for correcting it. You can have the tint removed or lightened to meet the 70% VLT rule for front windows. Some tint shops will remove and reapply tint to the legal limit. Keep the receipt showing the correction in case you're stopped before you've had it fixed.
Is reflective tint legal anywhere on my car?
No. Reflective tint is not allowed on any window in California, including the windshield. You can tint the top 4 inches of the windshield with non-reflective tint, but it cannot bounce light back outward.
How do I know what VLT percentage a tint shop is selling me?
Ask the shop to show you the product specifications or the film packaging, which lists the VLT. Reputable shops will provide this information and can explain the difference between 70% VLT and darker options. If a shop won't tell you the VLT, consider going elsewhere.