Construction
Paint Calculator: How Much Paint Do You Need?
Calculate paint needed for walls, ceilings, and rooms. Learn coverage rates and avoid buying too much or too little.
Buying the right amount of paint saves money and ensures color consistency across your project.
How to Calculate Paint Needed
1. Calculate wall area: (Length + Width) × 2 × Height
2. Subtract windows and doors: ~15 sq ft per door, ~12 sq ft per window
3. Divide by coverage rate: Most paint covers 350-400 sq ft per gallon
4. Multiply by number of coats (usually 2)
Paint Coverage Rates
- Standard latex: 350-400 sq ft/gallon
- Premium latex: 400-450 sq ft/gallon
- Primer: 250-300 sq ft/gallon (more porous surfaces)
Factors Affecting Coverage
- Surface texture (rough surfaces need more paint)
- Color change (dark to light may need extra coats)
- Paint quality (higher quality spreads better)
- Application method (sprayer uses more than roller)
Pro Tips
Always buy 10% extra for touch-ups. Keep leftover paint sealed for future repairs. Mix all cans together ("boxing") for color consistency.
Frequently Asked Questions
How much paint do I need for a 12x12 room?
A 12×12 room with 8-foot ceilings has about 384 sq ft of wall space. After subtracting doors/windows and applying 2 coats, you'll need about 2-3 gallons.
Does primer count as a coat of paint?
Primer is separate from paint. You typically need 1 coat of primer (on new drywall or drastic color changes) plus 2 coats of paint.
How do I calculate paint for ceilings?
Measure length × width for ceiling area. Ceiling paint typically covers 350-400 sq ft per gallon. One coat is usually sufficient.