Use this guide to estimate how many gallons you’ll need for painting the outside of your house:
Walls:
1. Measure the length of each outside wall and add together. Then multiply by the height to the gables.
Example: Your two-story house is a rectangle 20-feet deep and 50-feet wide. So 20+20+50+50 equals 140. Multiply 140 by the height, 18 feet, to get the total: 2,520 square feet.
2. To calculate the area of the gables, multiply half their width by their height and multiply by the number of gables.
Example: A house with two gables, 10-feet high and 50-feet wide. So 25 x 10 x 2 equals 500 square feet.
3. Add the results of steps 1 and 2, in this example: 2,520 + 500
3,020 square feet.
4. Divide that number by 400 (or the amount of coverage shown on the can label) to determine the number of gallons of paint needed: 3,020 divided by 400 equals 7.55 gallons.
Trim:
Count all windows and multiply by 15 square feet and count all doors and multiply by 20 square feet. Example: 10 windows x 15 equals 150 square feet, 2 doors x 20 equals 40 square feet for a total of 190 square feet–about a half-gallon or two quarts of trim paint.
