Estimate how much paint you need for a room based on its length, width, wall height, and number of coats.
This paint calculator helps you estimate the amount of paint required for the walls and, optionally, the ceiling of a rectangular room.
You only need three room measurements to use this calculator: length, width, and wall height.
The calculator first finds the total wall area using the perimeter of the room and its wall height.
If the ceiling option is selected, the ceiling area is also added. The total paintable area is then multiplied by the number of coats.
Finally, the result is divided by an estimated coverage of 350 square feet per gallon.
This is an estimate. Actual paint requirements can vary based on the type of paint, surface texture, color changes, application method, and the manufacturer's stated coverage.
Paint coverage tells you how much surface area can be covered by a certain amount of paint. The actual coverage depends on the paint brand, paint type, surface condition, and application method.
Always check the manufacturer's coverage information on the paint container before purchasing.
The number of coats depends on the condition of the wall, the existing color, the new color, and the type of paint being used.
It is usually helpful to have a small amount of extra paint available for touch-ups, future repairs, and areas that absorb more paint than expected.
Avoid buying too much extra paint, but consider rounding your calculated amount up to the nearest practical container size.
Your actual paint requirement may be different from the calculator estimate because several factors can change how much paint a surface absorbs.
The amount depends on the wall height, number of coats, ceiling, paint coverage, doors, windows, and surface condition. Enter your room measurements in the calculator above to get an estimate.
A common estimate is around 350–400 square feet per gallon for one coat, although actual coverage varies by product and surface.
If you are painting the ceiling as part of the same project, select "Yes" in the calculator so the ceiling area is included in the estimate.
Two coats are commonly used for a more even finish, but the required number depends on the existing surface, colors, paint type, and manufacturer's recommendations.
Yes. Rough, textured, or highly porous surfaces can absorb more paint than smooth walls, so the actual amount needed may be higher.
Keeping a small amount of extra paint can be useful for touch-ups and future repairs. Consider the final container sizes available from your paint manufacturer.