The legal limit for windshield and front‑side window tint in Montana for 2026 is a minimum of 35 % visible light transmission (VLT). Any tint darker than 35 % on these surfaces is prohibited, while back‑side, rear‑window, and windshield top‑strip tints may be darker with no specific statutory ceiling.
Montana’s Tint Regulations
Montana Code Annotated § 61‑5‑223 defines the permissible VLT for vehicle glass. The statute requires that front‑side windows and the windshield allow at least 35 % of visible light to pass through. This measurement is taken with a calibrated tint meter and reflects the percentage of light that remains visible after passing through the glass. The law does not set a VLT ceiling for rear‑side windows, rear windows, or the windshield’s upper 5‑inch strip, permitting owners to install darker films there if desired.
The 35 % threshold aligns with the majority of western states and is intended to balance driver visibility with the benefits of reduced glare and UV protection. For commercial vehicles, the same front‑side requirement applies, but fleets often adopt additional safety policies that limit tint on all windows.
Enforcement and Penalties
Law enforcement officers may conduct random or traffic‑stop inspections. If a vehicle’s front‑side tint falls below the 35 % VLT, the officer issues a traffic citation under § 61‑5‑223. Typical penalties include a $150 fine and a mandatory “tint correction” within 30 days, during which the vehicle must be re‑registered. Repeated violations can result in higher fines and potential suspension of registration until compliance is demonstrated.
How to Stay Compliant
- Purchase a certified tint meter – use it before installation to verify that the film meets or exceeds 35 % VLT on front windows.
- Select reputable installers – licensed shops are familiar with state requirements and can provide a written compliance statement.
- Keep documentation – retain receipts, the manufacturer’s VLT rating sheet, and the installer’s certification in the vehicle’s glove compartment.
- Schedule periodic checks – tint can degrade over time; a bi‑annual verification helps avoid inadvertent non‑compliance.
Impact on Safety and Visibility
Studies by the National Highway Traffic Safety Administration (NHTSA) indicate that excessive tint on front windows reduces driver reaction time, especially in low‑light conditions. The 35 % minimum VLT standard strives to preserve adequate peripheral vision and reduce the risk of accidents caused by delayed perception of hazards. Additionally, tint that meets this standard still blocks up to 99 % of ultraviolet radiation, protecting occupants from skin damage and interior fading.
What is the exact VLT percentage required for front‑side windows?
Front‑side windows must allow at least 35 % visible light transmission; any darker tint is illegal.
Can I use a darker tint on the rear windows?
Yes. Montana law places no VLT limit on rear‑side or rear windows, so darker films are permissible.
How is VLT measured?
VLT is measured with a calibrated tint meter that shines a light through the glass and records the percentage of light that passes through.
What are the penalties for non‑compliant tint?
The first offense typically results in a $150 fine and a requirement to correct the tint within 30 days. Subsequent violations may incur higher fines and registration suspension.
Do commercial vehicles have different tint rules?
Commercial vehicles must meet the same 35 % front‑side requirement, but many fleet policies impose stricter limits on all windows for safety and liability reasons.