Paint Calculator — How Much Paint Do I Need?

How Much Paint Do I Need?

The amount of paint you need depends on room size, number of coats, and wall surface texture. As a quick rule: one gallon covers 350-400 sq ft of smooth wall per coat. A standard 12x12 room with 8-foot ceilings needs about 1.5 gallons for two coats. Always buy a little extra for touch-ups — unopened paint can be returned, and leftover paint is useful for years.

Interior Painting Cost in 2026

DIY painting costs $50-$150 per room for paint and supplies. Professional painters charge $300-$800 per room, or $2-$4 per square foot of wall area. A whole-house interior (3 bedroom, 2 bath) typically runs $1,500-$4,000 for professional work. The biggest cost factors are room count, ceiling height, and how much prep work (patching, sanding, priming) is needed.

How Many Coats of Paint Do I Need?

Two coats is the standard for most projects and gives the best finish. You might get away with one coat if you're repainting the same color with a high-quality paint-and-primer combo. Use three coats when making a dramatic color change (especially going from dark to light), painting over a bold color like red or deep blue, or covering bare drywall or patched areas.

Tips to Save Money on Paint

Buy during holiday sales — Memorial Day, Labor Day, and Black Friday typically see 25-40% off at major retailers. Consider "oops paint" or mistinted gallons at Home Depot and Lowe's for $5-$10 per gallon (great if you're flexible on color). Mid-range paints like Behr Marquee or Sherwin-Williams Emerald offer excellent coverage in fewer coats, actually saving money over cheap paint that needs 3 coats.