Paint Coverage Calculator

One gallon of paint typically covers 350-400 square feet with a single coat on smooth, primed surfaces. Rough or textured walls, unpainted drywall, or porous surfaces may reduce coverage to 250-300 square feet per gallon.

Yes, subtract door and window areas from your total wall space. A standard door is about 20 sq ft and a window averages 15 sq ft. This prevents overbuying paint, though some prefer not to subtract small openings to ensure extra for touch-ups.

Most projects need two coats for even color and durability. Dramatic color changes (dark to light or vice versa) may require a tinted primer plus two coats, while touch-ups or similar colors might only need one coat.

Ceiling paint often has slightly better coverage (up to 400 sq ft/gallon) because ceilings are typically smoother and require less texture penetration. However, ceilings may need an extra coat since you're looking up at reflected light, which reveals imperfections more easily.

Buy at least one extra quart or round up to the nearest gallon for touch-ups, color matching issues, or application errors. Paint batches can vary slightly in color, so having extra from the same batch ensures perfect matches later.