Estimate paint needed for walls using wall dimensions, doors, windows, number of coats, and paint coverage rate in gallons or liters.
Wall area formula:
Wall width × wall height = total wall area
Paint formula:
(Paintable wall area × coats) ÷ coverage rate
This calculator subtracts windows and doors and adds extra material for waste or overage.
Knowing how much wall paint you need helps when planning room projects, budgeting, buying supplies, and reducing waste from overbuying or underbuying.
Adding extra paint is often useful for second coats, textured walls, touch-ups, and future repairs.
Your paintable wall area is the estimated surface area after subtracting doors and windows. The total wall paint needed depends on the number of coats, the coverage rate, and any extra percentage added.
The estimate helps you decide how much paint to buy for a single wall or large wall surface. Always check the paint can label for the manufacturer’s actual coverage recommendation.
Estimate the paintable wall area, multiply by the number of coats, then divide by the paint coverage rate.
Usually yes. Subtracting larger openings can make the wall paint estimate more accurate.
Many paints cover around 300 to 400 square feet per gallon, but the actual amount varies by product and surface.
Yes for many projects. Extra paint helps with waste, second coats, touch-ups, and future repairs.