Illinois's tint law (625 ILCS 5/12-503) works differently from Indiana's: the rear windows have no darkness limit of their own, but how dark they are decides what the front side windows may have. A lower percentage means a darker film.
The rules, window by window
- Windshield: a nonreflective strip reaching no more than 6 inches down from the top.
- Front side windows: nonreflective film letting in at least 35% of light, when no rear window is darker than 35%.
- Front side windows: at least 50%, when the rear windows are 30% or lighter, or are factory privacy glass.
- Rear tint darker than 30% leaves no allowance for front side film, so ask us before choosing dark rear shades on an Illinois car.
- Rear side and rear windows: no limit of their own, but a car with tinted rear glass needs a side mirror on each side.
- Officers metering the front windows allow a 5% variance.
- Medical exemption: a certified letter from an Illinois-licensed physician, renewed every 4 years, plus special plates or stickers from the Secretary of State.
Tinted in Indiana, registered in Illinois
Illinois's law follows the car, not the shop: an Illinois-registered car must meet Illinois's rules wherever it was tinted. Tell us your car is registered in Illinois when you book and we'll go over the legal shades with you.
625 ILCS 5/12-503 (ilga.gov), checked October 2026. A summary, not legal advice.