I bought my car used with tinted windows, but they just don't seem like they're as dark as legally possible.

Is there a quick way to determine if they are? I've heard that if you take your driver's license and put it behind the window, and can't see it, they are.

I want them darker so less of the FL sun comes into my car.

 

Im an inspector and i can get pretty close by eye but the main thing i go by, is when i step out to pull the car in if I can see the outline of the seat well then its 32+, If you cant see in at all its like 5-15% and if you can see alil it would prolly be like 20-32%. Easiest thing is just to go to a shop a couple counties over and get them to check it. That way when you go for an inspection they dont rake your *** cause they know what it is.