Paint Calculator
Find out how many gallons of paint you need for a room based on wall area, doors, windows and number of coats.
Result
- Paintable wall area
- Wall paint needed
- Ceiling area
- Ceiling paint needed
Results are rounded for ordering. Check product labels for exact coverage.
How to use this
The calculator subtracts about 21 square feet per door and 15 per window. Most paints cover 350 to 400 square feet per gallon per coat on smooth walls; textured or bare drywall covers less.
Buy one extra quart for touch-ups, and note the exact color and sheen for later.
Ready to price the job? Try the Interior Painting cost calculator for installed prices with materials and labor.
Common questions
How much does a gallon of paint cover?
Typically 350 to 400 square feet per coat on primed, smooth walls.
Do I need two coats?
Usually yes for a color change or a fresh look. Paint-and-primer products still often need two coats over a dark color.
How much paint for a 12 by 12 room?
Two coats on the walls take about two gallons; the ceiling takes about one.