wikiHow Price Per Square for House Painting Calculator To calculate the price per square foot for house painting, you'll need to determine the total surface area that you plan to paint and the cost of the paint and other materials you'll use. Here are the steps to follow: 1. Measure the height and length of each wall in feet, and multiply the height by the length to get the square footage of each wall. Add up the square footage of all the walls to get the total square footage of the walls. 2. Measure the length and width of the ceiling in feet, and multiply the length by the width to get the square footage of the ceiling. 3. Add the total square footage of the walls and ceiling together to get the total surface area that you'll be painting. 4. Determine the total cost of the paint and other materials you'll use for the job. 5. Divide the total cost by the total surface area to get the price per square foot. Here's an example to illustrate how this formula works: Let's say you're painting a room that has four walls, each measuring 8 feet high by 12 feet long, and a ceiling that measures 12 feet by 14 feet. The total surface area to be painted is 696 square feet. You purchase paint and materials for a total cost of $300. Price per square foot = total cost / total surface area Price per square foot = $300 / 696 sq. ft. Price per square foot = $0.43/sq. ft. So in this example, the price per square foot for house painting is $0.43. Page