How the Paint Calculator Works
Our paint calculator uses a standard formula to estimate your needs. First, it determines the total surface area of your walls by calculating the room's perimeter and multiplying it by the wall height: (2 * Length) + (2 * Width) * Height. It then subtracts the area of standard doors and windows to find the paintable surface area.
Finally, it divides this net area by the average coverage of a gallon of paint (approximately 350 sq. ft.) and multiplies by the number of coats you plan to apply. This gives you a reliable estimate of the total gallons you'll need to purchase.
Pro Tip: The Second Coat is Key
Almost every professional paint job requires two coats for even color, sheen, and durability. Our calculator assumes two coats by default, which is the most common and recommended practice for a high-quality finish.