Window Tint VLT Calculator
Find the real combined VLT of tint film on your glass and compare it with your local limit.
Legal limits differ by state and by window. Enter the figure from your local rules; this tool does not know them.
The number on a tint film box is not the number a meter reads on your car. Factory glass already blocks some light, so the film and the glass combine. This calculator multiplies the two so you can see the real visible light transmission (VLT) before you buy.
What VLT means
VLT stands for visible light transmission: the share of visible light that passes through the glass. A higher percentage is lighter. Film described as 35% lets 35% of light through; 5% lets only a sliver through.
combined VLT (%) = film VLT × glass VLT ÷ 100.
Light blocked = 100 − combined VLT.
Worked example
Common film shades
| Film VLT | On 80% glass | Typical look |
|---|---|---|
| 70% | 56% | Almost clear, heat and UV focused |
| 50% | 40% | Light smoke |
| 35% | 28% | Noticeably dark |
| 20% | 16% | Dark, limited night visibility |
| 5% | 4% | Very dark, often called limo |
Common mistakes
- Buying film by the box number and ignoring the glass. Combined VLT is always lower than the film number.
- Assuming one limit applies to every window. Rules often differ for the windshield, front sides and rear windows.
- Forgetting that some rear glass is factory tinted and can be darker than front glass.
- Choosing a very dark film without thinking about night driving and parking in poor light.
- Not asking the installer to show a meter reading after the job.
Frequently asked questions
What does 35% tint mean?
The film lets 35% of visible light through. On factory glass that already blocks some light the final reading is lower than 35%.
Is lower VLT always better?
No. Lower VLT is darker, which gives more privacy but reduces visibility at night and may break local rules.
Does ceramic tint use a different scale?
No. Ceramic and dyed films use the same VLT scale. Ceramic films are generally chosen for stronger heat rejection at a given darkness.
How can I check my real tint percentage?
A tint meter measures it directly. Many tint shops and some inspection stations have one.