Paint Calculator — How Much Paint Do I Need?
Estimate gallons of paint for interior walls and ceilings based on room dimensions and number of coats.
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Gallons
* Based on 350 sq ft/gallon coverage. Add 10% for textured or porous surfaces.
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Frequently Asked Questions
How much paint do I need for a 12×12 room?
A 12×12 room with 8-ft ceilings has about 384 sq ft of wall area (minus roughly 80 sq ft for doors and windows = 300 sq ft net). Two coats requires about 2 gallons.
How many square feet does one gallon of paint cover?
Most interior paints cover 350–400 sq ft per gallon on smooth walls. Textured or porous surfaces may require more. This calculator uses 350 sq ft/gallon as a conservative estimate.
How many coats of paint are needed?
Most projects need two coats for full coverage. Going from dark to light colors, or painting new drywall, may require three coats.
How do I calculate the paintable wall area in a room?
Measure the perimeter of the room, multiply by the ceiling height, then subtract 20 sq ft for each standard door and 15 sq ft for each window.
What is the difference between a gallon and a quart of paint?
A gallon covers 350–400 sq ft; a quart covers 87–100 sq ft. Buy a quart for small accent walls or touch-ups. For full rooms, gallons are more economical.