Room walls
Wall area = 2 × (length + width) × height
A room is treated as a rectangle with a uniform height.
How it works
How your measurements become a paint estimate.
We calculate the selected surfaces, subtract openings, then apply your number of coats and chosen product coverage.
Wall or ceiling
Area = length × width
Openings are subtracted before the number of coats is applied.
Paint volume
Paint = paintable area × coats ÷ coverage
Coverage is a product and surface assumption, not a geometric constant.
Containers
Containers = round up(paint volume ÷ container size)
The count uses the exact unrounded paint estimate.
Before you buy
What this estimate assumes
- Rooms, walls, ceilings, and openings are rectangular; room height is uniform and ceilings are flat.
- Openings do not overlap and are completely unpainted. Painted doors, trim, baseboards, and molding require separate estimates.
- All included surfaces use the same paint, coverage rate, and number of coats. Calculate walls and ceilings separately when products differ.
- Primer and losses from spraying, spills, or paint left in equipment are not included. Texture and porosity should be reflected in the coverage rate.
Coverage is a product assumption
The 350 ft²/US gal default uses the lower end of the 350–400 ft² range published by Sherwin-Williams. The metric value is its unit conversion. Always prefer the current label for the exact paint you plan to use.
Sources: Sherwin-Williams Paint Calculator and Benjamin Moore Paint Calculator. Product, surface condition, texture, and application method can change actual coverage.
Related calculators
Keep planning your project.
Use another Measivo calculator to estimate the next material on your list.