Paint Calculator
Estimate paint needed
Quick guide
What can Paint Calculator help you do?
Free paint calculator. Estimate liters and gallons needed from room dimensions, doors, windows, coats, and coverage rate.
Best for
Roughly estimate paint for the four walls of a rectangular room, comparing room dimensions, coat counts, and product coverage. The calculation excludes ceilings, trim, sloping walls, and multi-room lists. It does not price paint, estimate labor, or calculate a purchase budget.
How to use it
Enter room length, width, and height in meters, and coverage in square meters per liter per coat. Do not enter centimeter measurements unchanged. The sample room is 5 × 4 × 2.8 meters with two coats. Door and window counts must be nonnegative integers; other inputs must be positive.
How to read the result
Wall area is 2 × (length + width) × height, minus 1.8 square meters per door and 1.5 per window. Nonnegative area is multiplied by coats and divided by coverage. Results show liters and US gallons, without a waste allowance or rounding up to whole containers.
Privacy and limits
Room dimensions, opening counts, and coverage are calculated within the browser, without sending them to a quoting service or creating a renovation file. Copying writes to the clipboard. Site analytics still operates separately; no address, owner information, or floor-plan upload is needed.
Door and window areas are fixed assumptions, not adjustable measurements. A zero-liter result can mean that deductions exceed wall area, not that no paint is needed. Check the product coverage and actual surfaces, and account separately for waste, primer, and the container sizes you intend to buy.
Frequently Asked Questions
Are doors and windows subtracted?
Yes. The tool subtracts simple average door and window areas.
Should I buy extra paint?
Usually yes. Add margin for texture, touch-ups, and uneven surfaces.