Colorado requires every window except the windshield to let at least 27% of light through — front side, rear side, and the rear window all share the same floor. The one way to legally go darker in back with aftermarket tint: the front side windows and windshield both have to measure at least 70% VLT. Factory-installed windows approved under federal rules are carved out separately. This is set by Colorado Revised Statutes 42-4-227, the same statewide.
Colorado VLT limits by window
- Front side windows (driver + front passenger): must allow at least 27% VLT — the same floor that applies to every non-windshield window by default.
- Rear side windows and rear window: also at least 27% VLT, unless the front side windows and windshield both measure at least 70% VLT — in that case, the windows behind the driver may go below 27%. A metallic or mirrored appearance is still barred, and section 42-4-226(2) calls for an exterior mirror on each side when the rear windows obstruct the driver's rear view.
- Windshield: the windshield's main viewing area must allow at least 70% VLT. A separate non-transparent strip is allowed across the top, but only down to 4 inches from the top edge — that strip itself has no VLT floor to hit; it just can't be red or amber, can't distort vision or color perception, and can't add glare beyond an untreated windshield.
- Reflectance: no numeric cap — Colorado bans any window from presenting a "metallic or mirrored appearance" outright, regardless of what VLT it reads at.
- Color: the statute restricts color only for the windshield strip, which can't be red or amber or affect perception of primary colors; the section sets no separate color rule for other windows.
Medical exemptions
Colorado's statute doesn't include a medical exemption for darker tint. C.R.S. 42-4-227 makes no provision for a physician-certified waiver, and secondary reporting on the point is inconsistent, so don't treat "medical necessity" as a defense here without confirming current practice directly with the Colorado State Patrol or CDOT first.
Enforcement and penalties
Under C.R.S. 42-4-227(3), a violation of the window statute is generally a class B traffic infraction, but installing, covering, or treating a windshield or window so that it doesn't meet the 27%/70% requirements of subsection (1)(a) is a class A traffic infraction — a separate classification that applies to any person who installs, covers, or treats the glass, not only the driver; the general penalty table in section 42-4-1701(3)(a)(I) lists the same range for class A and class B. We haven't verified the dollar amounts for either class of infraction, so check the current penalty schedule or a local court for the exact total.
What this means when you're quoting a job
Colorado's class A infraction applies to any person who installs, covers, or treats a window so it misses the statute's limits, so a shop that installs film darker than 27% (or dark rear glass on a car whose front side windows and windshield don't both allow at least 70%) faces its own citation exposure, not just the customer. A window tint shop software tool that checks every window against Colorado's 27% floor before the quote goes out keeps that liability off the shop's books.
Frequently asked questions
What is the darkest legal tint in Colorado? Every window except the windshield must allow at least 27% VLT. The only way to go darker in back with aftermarket tint is if the front side windows and windshield both measure at least 70% VLT; factory-installed windows approved under federal rules are carved out separately.
Is 20% tint legal in Colorado? Not on the front side windows, and not on the rear windows either — unless the front and windshield are essentially untinted (70%+ VLT), in which case windows behind the driver may go below 27% (mirrored film is still barred, and exterior mirrors on both sides are required if the rear glass obstructs the driver's view).
Does Colorado allow a medical exemption for darker tint? The statute, C.R.S. 42-4-227, doesn't include a medical-exemption provision, and we haven't checked agency rules for a separate process. Confirm current practice with the Colorado State Patrol before assuming one applies.
Can a shop get in trouble for installing illegal tint, not just the driver? Yes. Installing, covering, or treating a window so that it doesn't meet the statute's light-transmittance requirements is a class A traffic infraction in Colorado — a separate classification from the class B infraction that applies to other violations of the section, though the general penalty range is the same for both classes.
Is mirrored or reflective tint legal in Colorado? No. Colorado bans any window from presenting a metallic or mirrored appearance outright, with no numeric reflectance threshold to work under instead.
This is general information based on Colorado's public statutes and reporting on C.R.S. 42-4-227, not legal advice — enforcement can vary and laws change over time, so confirm specifics with the Colorado State Patrol, CDOT, or a licensed attorney before you install, buy, or contest a citation.
Related
- State-by-state window tint laws (VLT limits) - Colorado shop market + VLT summary - Window tint percentages: what VLT, 5%, 20%, 35% mean - Window tint laws by state: the 2025 reference