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Calculate how much paint you need for walls and ceilings. Get gallons, liters, and cost estimates with automatic deductions for doors and windows.
This calculator provides estimates for planning purposes. Actual paint requirements may vary based on wall texture, paint quality, and application method. We recommend adding 10-15% extra for touch-ups.
Coverage rates assume smooth walls. Textured or porous surfaces may require more paint. Always check the paint can for specific coverage information.
Calculating paint requirements is essential for any painting project. Whether you're refreshing a single room or painting your entire home, knowing exactly how much paint you need prevents costly over-buying or project-stopping shortages. Paint coverage is measured by the area it can cover per gallon (typically 350-400 sq ft for standard paint). Our calculator considers wall area, deductions for doors and windows, ceiling coverage, and the number of coats to give you an accurate estimate.
Area = 2 × (Length + Width) × HeightCalculates the total area of all four walls in a rectangular room. This is the perimeter multiplied by the wall height.
Deduction = (Doors × 20 sq ft) + (Windows × 15 sq ft)Standard door (~3×7 ft) deducts 20 sq ft. Standard window (~3×5 ft) deducts 15 sq ft. Adjust for larger or smaller openings.
Gallons = (Paintable Area × Coats) ÷ Coverage RateDivide total paintable area by coverage rate (350 sq ft/gallon typical). Multiply by number of coats for accurate estimate.
Best for ceilings and low-traffic areas. Hides imperfections well but harder to clean. Coverage: 350-400 sq ft/gallon.
Popular for living rooms and bedrooms. Slight sheen, easy to clean. Coverage: 300-350 sq ft/gallon.
Ideal for kitchens, bathrooms, and trim. Durable and moisture-resistant. Coverage: 300-350 sq ft/gallon.
Best for trim, doors, and cabinets. Highly durable but shows imperfections. Coverage: 250-300 sq ft/gallon.
A 12x12 ft room with 8 ft ceilings has about 384 sq ft of wall space. After deducting for a door (~20 sq ft) and two windows (~30 sq ft), you have about 334 sq ft. For two coats at 350 sq ft/gallon coverage, you'd need approximately 2 gallons. Our calculator handles these calculations automatically.
Most quality interior paints cover 350-400 square feet per gallon on smooth, primed surfaces. Textured walls, porous surfaces, or dramatic color changes may reduce coverage to 250-300 sq ft/gallon. Always check the paint can label for specific coverage information.
Yes, two coats are recommended for best results. Two coats provide better coverage, more uniform color, and longer-lasting durability. You might need only one coat for touch-ups with the same color, or three coats when covering dark colors with light paint.
Yes, deducting for doors and windows gives a more accurate estimate. A standard door takes up about 20 sq ft and a standard window about 15 sq ft. Our calculator automatically deducts these areas to prevent over-buying paint.
Ceiling paint coverage is similar to walls: 350-400 sq ft per gallon. For a 12x12 ft ceiling (144 sq ft), you'd need about 1 gallon for two coats. Toggle the 'Include Ceiling' option in our calculator to add ceiling area to your estimate.
Interior paint is formulated for lower VOC emissions and easier cleanup. Exterior paint contains additives for UV resistance, weather protection, and mildew resistance. Never use interior paint outdoors as it won't withstand the elements.
Primer is recommended for: new drywall, stain blocking, covering dark colors with light paint, painting over glossy surfaces, or unfinished wood. Modern paint-and-primer combinations work for minor color changes on previously painted surfaces.
Textured walls require 10-25% more paint than smooth surfaces. Heavy textures like knockdown or popcorn may need up to 50% more. Our calculator assumes smooth surfaces, so add extra for textured walls based on the texture depth.