Customers throw around "5 tint" and "35 window tint" like everyone knows what they mean. Your installers do — but the customer usually doesn't. Here is the plain-English version you can hand a customer, plus how to use it to land on the right shade and the right price.
What does VLT mean? VLT stands for **Visible Light Transmission** — the percentage of visible light the film lets *through* the glass. It's the number behind every "window tint percentage" you've ever heard. A lower number means a **darker** tint (less light gets through); a higher number means a **lighter** tint (more light gets through).
So "35% tint" means the glass lets 35% of light through and blocks the other 65%. "5% tint" lets only 5% through — almost black. The percentage is about darkness and visibility, not about heat rejection: a light 70% ceramic can reject more heat than a near-black 5% dyed film, because heat rejection comes from the film technology, not the shade. (More on that in ceramic vs. carbon vs. dyed tint.)
One more wrinkle worth knowing: factory glass already has a VLT of its own (often around 70-80% on side windows), and the *net* VLT after film is roughly the film's rating multiplied by the glass's. That's why a "35% film" on factory glass can measure a little lower on a cop's meter — something a good shop accounts for when it quotes a legal shade.
What each tint percentage means (5%, 20%, 35%, 50%) The most-asked shades, lightest to darkest:
- 50% tint lets half the light through. Light — mostly for heat and UV — and barely reads as tinted from outside.
- 35% tint ("35 window tint") is the most popular shade: clearly tinted but you can still see in a little. Legal for front windows in many states and the safe default for a daily driver.
- 20% tint ("limo-ish") is dark and common on rear glass. In daylight you can just make out shapes inside.
- 5% tint ("limo" or "5 tint") lets almost no light through — effectively a privacy blackout. It's often illegal on front side windows and windshields, but common on rear and SUV cargo glass where many states allow any darkness.
A quick rule of thumb for the percentages most people ask about: 35 is the everyday choice, 20 is dark-but-livable on the rear, and 5 is the blackout look that's usually rear-only and frequently illegal up front.
Window tint percentage chart (all common shades) The full lineup shops actually sell, lightest to darkest, at a glance:
- 70% VLT — barely visible from outside. Mostly a heat/UV layer for customers who want zero look change. Common on windshields where states allow a clear or near-clear strip.
- 50% VLT — light, factory-look tint. Reads as "slightly darker glass," not "tinted car."
- 35% VLT — the everyday front-window shade. Clearly tinted, still easy to see in and out.
- 30% VLT — a shade darker than 35 without crossing into "can't see who's driving" territory. A common step-up choice on the rear when 35 feels too light.
- 20% VLT — dark. Popular rear-and-back-glass shade; you can make out shapes inside but not faces clearly.
- 15% VLT — very dark, near the edge of what most states allow anywhere on the vehicle. Rear-only in most markets.
- 5% VLT — "limo black." Effectively a privacy blackout, almost always rear-and-back-glass-only since it's illegal up front in nearly every state.
What each shade looks like — day vs. night The conversation customers actually care about is visibility. Frame it that way:
- During the day, 35% looks darker than it really is because of the reflection on the glass.
- At night, every shade looks darker from the inside — a 20% rear window can make backing into a dark driveway feel sketchy, and 5% on a side window you actually use is rough after dark. Steer nervous drivers toward 35% up front and save 5-20% for the rear, where rearward visibility matters less.
Tell customers the law before they ask Front-window VLT limits vary by state, and a ticket is the fastest way to a one-star review of *your* shop. A 5% front window is illegal almost everywhere; even 35% is too dark for the front in a handful of strict states. Keep your state's limit visible at the counter and quote a legal shade up front. We keep plain-English tint-law summaries — front-side VLT, rear and back-glass limits, windshield rules, and medical exemptions — by state on our [regions](/regions) pages. The windshield is its own special case: see the [windshield tint laws, options, and cost guide](/guides/windshield-tint-laws-options-cost) for the AS-1 line and strip rules.
How to calculate your actual (net) VLT The film's printed percentage isn't what a meter reads on the car — factory glass already blocks some light on its own, so the two multiply together. Take the film's VLT, multiply by the glass's own VLT (commonly 70-80% on side windows), and the result is roughly what a roadside meter will measure:
- 35% film on 80% glass: 0.35 × 0.80 ≈ 28% net VLT
- 35% film on 70% glass: 0.35 × 0.70 ≈ 24.5% net VLT
- 20% film on 80% glass: 0.20 × 0.80 ≈ 16% net VLT
- 5% film on 80% glass: 0.05 × 0.80 ≈ 4% net VLT
That's why a "35% film" can measure well under 35% on an officer's meter, and why quoting strictly by the film's printed number — without accounting for the glass underneath — is how a shop accidentally installs an illegal shade on a customer's car. When you're within a few points of your state's legal minimum, quote a lighter film than the limit, not right at it.