To get basic measurements, measure the length and width of each wall you want to paint in inches. Multiply the length and height together, and divide by 144. This will give you the square footage for each wall. A gallon of paint typically covers around 400 square feet. In some cases, you may need a primer 2 first, then a single coat of paint, meaning that you may need one gallon of primer and one gallon of paint to cover 400 square feet. However, if the wall requires multiple coats, this will increase the total amount of square footage required, and therefore the amount of paint.
When calculating total cost of your project, one of the most important factors to consider is the paint itself. Paint costs will be determined by the quantity of paint and primer required to complete your project, as well as the quality of the paint you choose. You can use this paint calculator to estimate how much paint you will need.. Once you have an idea what you're working with, go to your local home improvement store and compare the costs of a gallon in person. Painting professionals can also quote average prices from their years of experience working with different paint qualities.