A: Hi,
One gallon of Behr Premium Plus Ultra Interior paint will provide enough paint for one coat of product for between 250 and 400 square feet. The reason there is a range is that the spread rate will vary depending on what you are painting. Paint will go further on smooth, sealed surfaces and, as you would expect, you will need more paint for rough, porous or textured surfaces. Your application tools and technique will also have some affect on the spread rate as well.
To determine how many gallons you will need for your project, there is a handy paint calculator on behr.com.
Thanks for your inquiry!