Paint Calculator
Estimate how many gallons (or liters) of paint to buy. Accounts for room dimensions, number of coats, and door/window subtraction.
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About Paint Calculator
Coverage
Standard latex paint covers about 350 sq ft per gallon on smooth, primed surfaces. Textured walls or porous surfaces (new drywall, raw wood) may need 250-300 sq ft per gallon — buy 15-20% extra to be safe.
Primer
Use primer when painting over dark colors, raw drywall, stains, or with bold accent colors. Primer is typically 1 coat covering 200-300 sq ft per gallon. Self-priming "paint and primer in one" works for refresh jobs but not big color changes.
Buy extra
Add 10-20% for touch-ups now and later. Most colors are custom-tinted — getting an exact match later is hard. A small can of leftovers is gold five years from now when you need to fix a scuff.