VLT Calculator
Estimate installed automotive VLT using the unfilmed glass VLT and the manufacturer-published film VLT.
Enter VLT values
Use the measured or published VLT of the unfilmed glass and the manufacturer-published film VLT.
Why divide by 0.90?
The simple method — glass VLT × published film VLT — understates the result because the film's published VLT already includes the effect of the nominal 90% VLT clear glass used for performance testing.
The 90% reference glass transmits approximately 90% of visible light. The remaining 10% is accounted for by visible reflection and absorption. Dividing by 0.90 removes the reference-glass contribution and gives a better estimate when the film is applied to automotive glass with a different VLT.
Quick reference table
Estimated installed VLT using the corrected formula. Film VLT is shown down the left; unfilmed glass VLT is shown across the top.
| Film VLT |
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Estimated values only. Actual glass and film VLT can vary from published nominal values, and a field meter may read differently. Verify local legal requirements independently.