Figure out exactly how many gallons of paint you need for any room, wall, or surface. Accounts for doors, windows, multiple coats, and primer. Get your paint quantity right the first time and avoid extra trips to the store.
Adds length × width to total area
Primer coverage: 300 sq ft/gallon. Recommended for new drywall, dark-to-light color changes, or stain blocking.
Painting a 12×14 foot bedroom with 8-foot ceilings, 2 doors, and 2 windows? The total paintable wall area is about 346 square feet. At standard coverage of 350 square feet per gallon with 2 coats, you would need 2 gallons of paint. Adding primer brings the total to about 4 gallons. At $35–$50 per gallon for quality interior paint, budget around $140–$200 for paint and primer.
| Surface Type | Coverage per Gallon |
|---|---|
| Smooth drywall (primed) | 350–400 sq ft |
| Textured walls | 250–300 sq ft |
| New/unprimed drywall | 250–350 sq ft |
| Primer | 200–300 sq ft |
| Ceiling paint | 350–400 sq ft |
With 8-foot ceilings, 2 doors, and 2 windows, you need approximately 1.5–2 gallons for two coats. Round up to 2 gallons.
Two coats is standard for most jobs. Use three coats when making a dramatic color change (especially light over dark). One coat may be sufficient when touching up or painting the same color.
Yes if you are painting new drywall, covering stains, making a major color change, or switching between oil and latex. On previously painted walls in good condition with a similar color, you can usually skip primer.
A gallon of interior paint covers approximately 350–400 square feet on smooth, primed surfaces. Textured walls, porous surfaces, and dark colors reduce coverage by 15–25%.
Always round up to the next full gallon. Having leftover paint is useful for touch-ups, and partially used gallons are difficult to color-match later.
Not sure how much a surface absorbs? See our paint coverage reference for coverage rates by surface type.
Typical Results
💡 If the result is over 5 gallons for a single room, double-check your room dimensions.
Common Mistakes