Window Tint VLT Calculator
See the real light transmission of a film over your glass — the two VLTs multiply — and check it against a legal minimum you set.
Combined VLT
The combined reading is below the minimum you entered — a lighter film would be needed to comply.
A tint meter reads the film and glass together, so the combined figure — not the film’s rated VLT — is what a roadside check measures.
Why a 35% film isn’t a 35% window
Tint film is rated for the light it passes on its own, but you never install film in mid-air — you install it on glass that already blocks some light. Light has to get through both layers, so the transmissions multiply: a 35% film on glass that passes 80% gives a window that passes about 28%, darker than the film’s label suggests.
That combined figure is the one that matters, because it’s what a tint meter reads at the roadside and what a legal limit is written against. Enter your film and glass VLT, set the limit that applies where you drive, and the tool shows the true result and whether it clears the line — but confirming the actual local law is on you.
Frequently Asked Questions
How do film and glass VLT combine?
They multiply as fractions. A 35% film means 35% of the light reaching it passes through; if the glass under it already passes 80%, the pair transmits 0.35 × 0.80 = 0.28, or 28%. So a 35% film on typical glass does not give a 35% window — it gives 28%.
What is VLT?
VLT stands for Visible Light Transmission — the percentage of visible light that passes through a window. A higher VLT is lighter and clearer; a lower VLT is darker. Tint film is rated by the VLT of the film alone, not the film plus your glass.
Why check the combined figure against a legal limit?
Tint laws are written in terms of the total light that passes through the window as installed, which is what an officer's tint meter measures on the glass. That's the combined film-plus-glass VLT — so it's the number to compare against a legal minimum, not the film's rated VLT on its own.
What VLT does bare car glass have?
It varies by vehicle and window. Many factory side windows sit around 70–88% VLT before any film, and some come lightly tinted from the factory, which lowers the starting point further. Measure or look up your glass rather than assuming it's perfectly clear.
Does this tool tell me what's legal where I live?
No. Legal minimum VLT differs widely by country and by U.S. state, and often differs for the windshield, front sides, and rear windows, with exemptions for medical needs and certain vehicles. The tool only checks your combined VLT against a limit you type in — always confirm the exact local rule.
Estimates for planning — not professional automotive, installation, or legal advice. Tint laws vary by state and country and by window; verify the exact local tint law and measure the installed result.