Question: How much Paint Do I Need For a 12' X 12' Room?
Answer: Assuming that this room has standard 8 foot ceilings, here is how you figure out how many square feet you have. You multiply your 12 foot wall by 4 because you have 4 walls. So 4 x 12 = 48 feet. Then you multiple your 48 feet of wall space by 8. 48 x 8 = 384 square feet.
A typical gallon of paint will cover 400 square feet with one coat. So a two coat job will take 2 gallons of paint. Some people will subtract square footage for windows, doors and closets. However, if you keep these in the measurements you should have enough paint left over for touch-ups.