Is a 20 percent tint legal in Montana in 2026? Yes, it is legal on the front side windows for passenger vehicles, provided the windows meet the required minimum visible light transmission (VLT) of 20 percent and the rear windows allow at least 35 percent VLT. Drivers must also have side‑mirror visibility that complies with state standards. These rules are codified in Montana Code Annotated § 61‑1‑221 and have been unchanged since the 2022 amendment that clarified front‑window limits.
What the Law Says
Montana’s vehicle‑window‑tint regulations are based on VLT, the percentage of outside light that passes through the glass. For passenger cars the law permits:
- Front side windows – minimum 20 percent VLT.
- Front windshield – must be clear, though a non‑reflective strip at the top may have up to 5 percent tint.
- Rear side windows and rear windshield – minimum 35 percent VLT.
These thresholds are measured with a calibrated tint meter; any lower reading is considered a violation (Montana Dept. of Transportation, 2025). The law applies to all motor vehicles operating on public highways, including rideshare and rental cars.
Exceptions and Special Cases
Certain vehicles enjoy more lenient limits. SUVs, trucks, and vans may tint rear windows to as low as 20 percent VLT, but the front side windows still must meet the 20 percent rule. Medical exemptions exist for drivers with a physician‑signed statement, allowing darker tints for conditions like photosensitivity, but the exemption must be displayed on the vehicle registration (Montana DMV, 2025).
How to Ensure Compliance
- Buy a certified tint film—look for a product that lists the VLT percentage and has a UL or ANSI certification.
- Use a professional installer—they will calibrate the film to the exact VLT and provide a receipt that can serve as proof of compliance.
- Obtain a post‑installation inspection—the DMV offers a free VLT verification at designated inspection stations. Keep the inspection sticker on the vehicle as evidence.
Following these steps minimizes the risk of a ticket during a routine traffic stop.
Penalties for Violation
If a law‑enforcement officer detects illegal tint, the driver receives a citation and must either remove the tint or obtain a corrective inspection within 30 days. Fines range from $150 to $400 per window, plus court costs if the case goes to municipal court (Montana Traffic Code, 2024). Repeated offenses can lead to increased fines and potential suspension of vehicle registration until compliance is demonstrated.
Frequently Asked Questions
Can I have a darker tint on the rear windows if I have a medical exemption?
Yes. A physician’s statement authorizing a darker tint up to 5 percent VLT is accepted, but the exemption must be filed with the DMV and displayed on the registration.
Does the 20 percent rule apply to all vehicle types?
No. While passenger cars must meet the 20 percent minimum on front side windows, larger vehicles such as trucks and SUVs may have rear windows tinted to 20 percent, but front side windows remain subject to the same 20 percent requirement.
How is VLT measured during an inspection?
A handheld spectrophotometer measures the amount of light that penetrates the glass. The device displays the VLT as a percentage; any reading below the legal minimum results in a citation.
Will aftermarket window films affect my windshield wiper performance?
High‑quality films are designed to be thin enough not to interfere with wiper contact. Poorly applied or overly thick films can cause streaking, which may be cited as a safety hazard under Montana’s vehicle equipment standards.
If I buy a car with factory‑installed tint, do I still need to verify compliance?
Factory tint is presumed compliant, but the DMV recommends a quick VLT check during the annual vehicle inspection to confirm the manufacturer’s specifications match current state limits.