Determining the amount of paint needed for a 1500-square-foot house exterior depends on several factors, including the type of siding, the number of stories, and the desired number of coats. A general guideline is to estimate paint coverage based on the surface area to be painted.

Here are the basic steps of calculation…

1. Calculate the Surface Area – Measure the exterior walls’ total surface area to be painted. For a rectangular or square-shaped house, you can calculate this by multiplying the perimeter of the house by the height of the walls. For example, if the house has 4 walls each 30 feet long and 10 feet high, the total surface area would be 4 * 30 * 10 = 1200 square feet.
2. Consider Overlap and Waste – Factor in some extra paint for overlap, waste, and touch-ups. A common rule of thumb is to add 10-20% to your total paint estimate to account for these factors.
3. Determine Paint Coverage – Paint coverage typically varies based on the type of paint, surface texture, and application method. Most paint cans provide coverage estimates per gallon. For exterior surfaces, coverage usually ranges from 250 to 400 square feet per gallon for a single coat, depending on the paint type and surface porosity.
4. Calculate Paint Needed – Divide the total surface area (adjusted for overlap and waste) by the paint coverage per gallon to determine the total number of gallons needed.

For example:

• Total surface area: 1500 square feet
• Adjusted for waste: 1500 square feet + 10% (150 square feet) = 1650 square feet
• Coverage per gallon: Let’s assume 300 square feet per gallon
• Gallons needed: 1650 square feet / 300 square feet per gallon = 5.5 gallons

In this example, you would need approximately 5.5 gallons of paint for one coat. If you plan to apply multiple coats, you’ll need to adjust your estimate accordingly.

It’s always a good idea to consult with a paint professional or use a paint calculator provided by paint manufacturers to get a more accurate estimate based on your specific circumstances and preferences.