How Much Paint Do I Need for a Room?
For a standard room, calculate wall area using: 2 x (length + width) x height. Then divide by 350 sq ft (typical gallon coverage). A 12x10 ft room with 8 ft ceilings needs about 1.3 gallons for one coat. Use our Paint Coverage Calculator for exact amounts.
Key Takeaways
- Paint coverage depends on wall texture, paint quality, and color change.
- Subtract window and door areas (about 20 sq ft per door, 15 sq ft per window) for more precise estimates.
- Dark colors covering light colors typically need 2-3 coats; light over dark may need primer plus 2 coats.
Explanation
Paint coverage depends on wall texture, paint quality, and color change. One gallon typically covers 350-400 square feet on smooth walls. Textured walls or drastic color changes may require more paint or additional coats.
The formula for wall square footage is: 2 x (room length + room width) x ceiling height. This calculates all four walls. For example, a 12x10 room with 8-foot ceilings has: 2 x (12 + 10) x 8 = 352 square feet of wall space.
Most painting projects require two coats for even coverage, especially when changing colors. Always round up when buying paint - it's better to have extra for touch-ups than to run short mid-project.
Paint quality directly affects coverage rates. Premium paints from brands like Benjamin Moore Regal or Sherwin-Williams Duration contain more pigment and resin per gallon, often covering in fewer coats. A gallon of budget paint at $25-30 may cover only 250-300 square feet and need 3 coats, while a premium gallon at $50-70 covers 350-400 square feet in 2 coats—making the per-square-foot cost roughly similar.
Primer is a separate calculation that many people overlook. New drywall, bare wood, and stain-blocking situations each require primer before paint. Primer typically covers about 300 square feet per gallon. Tinted primer matched to your topcoat color can eliminate an entire coat of paint, saving both time and money on dramatic color changes like going from dark red to white.
Room size determines your purchase: a small bedroom (10x10 ft, 8 ft ceilings) has about 320 sq ft of wall area and needs 1 gallon for two coats. A standard bedroom (12x12 ft) needs 1.5 gallons. A large living room (18x14 ft) has roughly 512 sq ft of wall space and requires 2 gallons for two coats. Bathrooms and half-baths typically need only a quart to a half gallon. Always buy at least one extra quart for future touch-ups, since matching exact colors later from a new batch is nearly impossible due to slight pigment variations between production runs.
Things to Know
- Subtract window and door areas (about 20 sq ft per door, 15 sq ft per window) for more precise estimates.
- Dark colors covering light colors typically need 2-3 coats; light over dark may need primer plus 2 coats.
- Ceiling paint is calculated separately: length x width of the room.
- Textured surfaces like stucco, brick, or heavy knockdown texture can increase paint consumption by 25-50% compared to smooth drywall.