ABOUT AUTO PAINT - HOW MUCH PAINT DO I NEED
HOW MUCH PAINT DOES IT TAKE TO FULLY PAINT A CAR?

It depends on the size of the vehicle, and the type of paint used. There are formulas for sq. ft. coverage, but in my experience are not always reliable. Let's take a 92 Cutlass Ciera for example, which would be a fairly common size. In a base coat /clear coat (BC/CC) application, I would mix 2 quarts of base coat, (perhaps one quart with an HVLP) which thinned to spraying consistency would give me a gallon of spray-able material, and should provide adequate coverage. However, some are more transparent than others, and additional or less material may be required.
Paint booth lighting is essential to ensure proper coverage. After applying the base coat, I would mix two quarts of clear, which reduced would give me three quarts of spray-able material (two coats at approx 1 1/2 quarts per coat). An additional third coat could be applied if desired, but be sure to watch for excessive film build which can lead to dulling or solvent popping problems. If you don't have access to a paint mixing system, then buy more than you need. There is no way to fix a paint job that does not have adequate coverage except for repainting the entire car.