Umm, some tint shops have the right equipment for it...I'm not too familiar with how it works, but it measures the amount of light coming through the windshield.
oooooooooooo, i get it. thanks i think im gonna tint my front windsheild. wat % would you suggest
BTW, when I said 5% front no limit rear, I mean 5% for the front side windows (not the windshield), and no limit for the back sides and the rear. It is illegal anywhere to tint your front windshield (with the exception of a small strip at the top in some states), and I really doubt any shop in their right mind would do it for you. Not to mention the fact that it would be very stupid, and you'd be pulled over for it and slapped with a fine.