Paint Gallons Calculator
How to Estimate Paint for a Room
Calculating the amount of paint you need before starting a project saves time and ensures you don't overbuy or run out of supplies mid-job. This calculator helps you determine the exact number of gallons required based on the dimensions of your room and the number of openings.
Understanding the Formula
The basic formula for calculating paint involves finding the total wall area and subtracting the area of windows and doors. Here is the breakdown:
- Wall Area: Calculate the perimeter of the room (Length + Width × 2) and multiply it by the wall height.
- Subtractions: Subtract approximately 15 square feet for each standard window and 20 square feet for each standard door.
- Coats: Multiply the final square footage by the number of coats you intend to apply (usually 2 for color changes).
Standard Paint Coverage
Most standard interior paints cover between 350 to 400 square feet per gallon. However, this can vary based on the texture of the walls and the quality of the paint. Rough surfaces like stucco or brick may require up to 25% more paint. Always check the label on your specific paint can for the manufacturer's estimated coverage rate.
Tips for Accurate Measurement
For the most accurate results, measure the length and width of the room at floor level. If your ceiling height varies (e.g., vaulted ceilings), measure the average height or the highest point to ensure you have enough paint. It is always better to have a little extra paint for touch-ups than to come up short.