How much paint do you need to cover a room? It can be frustrating to make a second trip to the paint counter, after falling short of the needed paint for your project, or ending up with cans of unused paint that you didn’t need to buy. Though materials and coats can change the amount of paint you need, there are usually a few guidelines to follow.
What You’re Painting
A room that only needs paint on the walls will require less paint than a room that is going to be painted in its entirety including walls, doors, moldings and ceiling. Additionally, homes with unfinished or dark walls will need a second coat of paint, which means that you’ll need twice as much paint as a house with light walls.
The Paint Formula
The square foot formula is a good place to start, but it is merely a guideline and not precisely accurate as to how much paint you will need. As a rule of thumb, you can cover 350 square feet of wall with a single coat with a gallon of paint. Measure the length of your walls, and multiply the sum by the height of your walls. If you’re painting the doors and windows, divide the number by 350 in order to determine how many gallons you’ll need.
If not painting doors and windows, subtract 20 square feet for every door and 15 square feet for every window from the original product. Then divide the number you get by 350.
Remember, this is only a guideline. Some rooms of the same size may take two gallons in one room and four gallons in a similar room.
TIP: Doityourself’s painting consultant Edward Kimble, author of Interior House Painting Blog, suggests, “Count on applying two coats of paint, because it is usually necessary unless you are covering the walls using the exact same color.”
The Test Coat
Even a good professional painter will not be able to accurately estimate how much paint will be used. It depends upon the porosity and type of surface to be painted and, as mentioned above, most rooms will need a second coat. When covering a dark wall with light paint, two coats will be necessary. Buy one or two gallons of paint to start an average size room. See how far the paint is actually going on that wall with that color, and you should have a better idea as to how much more paint is needed to finish the job. Most paint suppliers these days only have a couple of paint bases, and the paint is non-returnable because it is a custom color that cannot be used elsewhere.
TIP: Edward says, “Start with less paint than you think you will need. Since most paint is a custom color and non-returnable, you cannot return paint to the paint store, but you can always buy more.”
Edward Kimble, professional painter and author of Interior House Painting Blog, contributed to this article.