Paint Calculator
Interior walls from room size; subtract doors and windows; coats × coverage (m²/L, ft²/L, or ft²/gal); liters or gallons and optional cost.
Wall area uses four walls only (no ceiling): 2 × height × (length + width), unless you enter a custom wall area for odd shapes.
Opening areas subtract from that total; volume = paintable area × coats ÷ spread rate. Label coverage beats guessing—add extra for texture or first coat.
Room dimensions
Four walls only (no ceiling). Wall area ≈ 2 × height × (length + width). Override below if the room is not a simple rectangle.
If set, this replaces the calculated wall area for paint math (odd-shaped rooms). Leave empty to use dimensions above.
Doors
Subtract painted door openings on the walls. Use 0 doors if none apply.
Windows
Same size per count. For mixed sizes, enter total window area manually via custom wall area or adjust counts after computing once.
Amount of paint needed
Coverage is the can label spread rate (area per liter or per gallon). Porous or first-time surfaces often need +20–30% in practice.