How to Calculate the Amount of Paint Needed
When you’re planning a painting project, knowing how to determine the amount of helps you save on costs by allowing you to calculate cost based on this. This calculation can be accomplished using tools are available online or be done using a spreadsheet or sheet of paper. The square footage method is a good start if you have no idea at all how much paint will be needed, but it is only a “ballpark” method.
Measure the Surface Area
The area of the space the paint is needed for is the most important factor in calculating the amount of paint. To calculate area, measure the length and width of the surface being painted. Multiply length by width to obtain the square footage.
TIP: Painting professional Edward Kimble, author of Interior House Painting Blog, adds, “The type of wall (whether plaster, drywall or another material), and the nature of the surface and how “thirsty” or pourous the walls are are variables that should be taken into consideration. Plaster walls generally require less paint than drywall, as plaster does not absorb paint as much as drywall.”
Determine the Amount of Paint Coverage
With the square footage written down, you need to determine the amount of area a gallon of paint will cover. This calculation can typically be done online or in-store. The average gallon can of paint will cover a surface area of up to 350 square feet. Taking this into consideration, you should be able to calculate how much paint you need by taking 350 and dividing it by the square footage you measured. Round up to the nearest number.
For example, let’s say you are painting a bedroom wall. The wall measures 6 feet by 12 feet, which is a total area of 96 square feet. Divide the number of square feet by the square foot coverage of the paint. Based on an average of 350 square feet per gallon, it would take about 1/3-gallon of paint to cover the wall. If we were to say that the average cost for a gallon of premium semi-gloss interior paint is $25, the cost to paint the bedroom wall would be $8. Of course, different types provide different levels of coverage, and even different colors of the same type will cover differently. Certain colors cover in one coat, whereas other colors require two coats.
TIP: Edward says, “The existing color that will have to be covered is also a factor. For example, covering white walls with white paint can probably be done with one coat, whereas covering pink paint with the same white paint will definitely require two coats.”
Most paint stores and home improvement centers will help you with the determination of how much paint is needed based on the size of the project. Other considerations regarding cost include the windows, doors and trim. These items will increase the cost for paint.
TIP: Edward adds, “I would suggest to the DIY person who has no idea how much paint to buy use the square foot method to start, buy a few gallons of paint and see how far it actually does go, then purchase the rest of the paint with this knowledge.”
Using the online paint coverage calculators that are provided on many websites is the best way to calculate the amount of paint needed. These tools are designed to calculate the rounded value of paint needed in gallons and quarts. These figures can be multiplied by the cost for paint and you will have your cost.
Edward Kimble, professional painter and author of Interior House Painting Blog, contributed to this article.