Indiana's tint law (Indiana Code 9-19-19-4) sets one standard for the windshield strip, the side wing windows, the front door windows and the rear window: the film must let in at least 30% of visible light and reflect no more than 25%. A lower percentage means a darker film.
The rules, window by window
- Front door windows: 30% or lighter (at least 30% of visible light gets through).
- Rear window: 30% or lighter.
- Back door windows (the side windows behind the driver): the statute doesn't list them. It names only the windshield, the side wing windows, the front door windows and the rear window, and the State's own FAQ says the same.
- Windshield: the top strip only, no lower than the AS-1 line marked on the glass.
- Reflectivity: no more than 25%.
- Factory tinted glass that meets the federal glass standard (FMVSS 205) is allowed; carry the proof in the car.
- Medical exemption: a statement from an Indiana-licensed physician or optometrist, carried in the car and renewed every year.
- Driving into Illinois: Illinois's tint rules don't apply to cars registered in another state (625 ILCS 5/12-503(f)(2)).
Driving into Illinois
Illinois exempts cars registered in other states from its tint rules (625 ILCS 5/12-503(f)(2)), so an Indiana-registered car tinted to Indiana’s law can drive in Illinois.
Indiana Code 9-19-19-4 (iga.in.gov), checked October 2026; the State of Indiana's own FAQ (faqs.in.gov) lists the same windows. A summary, not legal advice.