It will take 2 to 3 gallons of paint to paint an 800-square-foot house. One to one and a half cans can cover 400 square feet.
When considering the square footage of a house, take doors and windows into consideration. When using a lighter color, or a cheaper brand of paint, more coats may be required, and this will increase the amount of paint needed. On average, four 1-gallon cans of paint can cover up to 1,600 square feet, which is equal to the size of several average-sized rooms. Users should choose interior or exterior paint depending on their needs.