Use this free paint calculator to find out how many gallons of paint you need for your project. Enter the room dimensions or total square footage, the number of coats, and the paint coverage rate to get an accurate estimate with no guesswork.
How to use this Paint Calculator
1. Enter your room's length and width in feet.
2. Enter the ceiling height in feet.
3. Enter the number of doors and windows — the calculator subtracts approximately 21 square feet per opening (standard door size) from the total wall area.
4. Select the number of coats — most interior paint projects require 2 coats for even coverage, especially when changing colors significantly.
5. Select the paint coverage rate — check your paint can label for the specific coverage. Standard latex paint typically covers 350 to 400 square feet per gallon.
6. Click Calculate Paint Needed to see your total paintable area in square feet, gallons needed, and quart equivalent.
Frequently asked questions
How many square feet does a gallon of paint cover?
Most standard interior latex paints cover 350 to 400 square feet per gallon per coat. Premium paints and those with higher solids content may cover up to 450 square feet per gallon. Flat or matte finishes typically offer slightly less coverage than eggshell or satin finishes. Always check the specific coverage rate on the paint can label for the most accurate estimate.
Do I need a primer before painting?
Primer is recommended when painting over a dark color with a light one, painting new drywall, painting over stains or repairs, or switching between paint types (latex over oil-based). A good primer can eliminate the need for an extra coat of paint, potentially saving money. Self-priming paints are available but often require two coats to match the coverage of a dedicated primer plus one coat of paint.
How do I calculate paint for ceilings?
Ceiling paint is calculated separately from wall paint. Simply multiply the room length by the room width to get the ceiling square footage. For a 14 by 12 foot room, the ceiling is 168 square feet. At 400 square feet per gallon, one gallon covers the ceiling with a single coat. Ceilings typically only need one coat of a dedicated ceiling paint.
What finish should I use for different rooms?
Flat or matte finish is best for low-traffic areas like adult bedrooms and formal dining rooms. Eggshell is the most popular choice for living rooms and hallways as it resists light scrubbing. Satin is ideal for kitchens and bathrooms due to its moisture resistance. Semi-gloss and gloss are best for trim, doors, and cabinets as they are highly washable and durable.
How long does it take for paint to dry between coats?
Most latex interior paints are dry to the touch within one to two hours but should not be recoated for at least four hours. Oil-based paints take longer — typically 24 hours between coats. Low temperatures and high humidity slow drying time significantly. Always follow the manufacturer’s recoat time listed on the paint can label.