How Much Paint Do I Need?
A complete guide to calculating paint quantities for interior painting projects.
Understanding Paint Coverage
One gallon of paint typically covers 350-400 square feet of smooth wall surface. For textured or porous surfaces, expect 250-300 square feet per gallon. Always check the manufacturer label for the specific coverage rate of your chosen paint.
How to Calculate Paint Quantity
To calculate paint needed: (1) Measure room perimeter = 2 × (Length + Width). (2) Multiply by wall height for gross wall area. (3) Subtract door area (20 sq ft per door) and window area (15 sq ft per window). (4) Multiply by number of coats. (5) Divide by coverage per gallon.
How Many Coats Do You Need?
Most interior walls need 2 coats for even coverage. Dark-to-light color changes may require 3 coats. Primer counts as a separate coat and typically covers 200-300 sq ft per gallon. For new drywall, always apply primer first.
Paint Types and Their Coverage
Flat/Matte: Best for ceilings and low-traffic areas. Eggshell/Satin: Good for living rooms and bedrooms. Semi-Gloss: Ideal for trim, doors, and bathrooms. Gloss: Best for high-moisture areas and surfaces that need frequent cleaning.
Money-Saving Tips
Buy paint in 5-gallon buckets for large projects (saves 15-25% vs individual gallons). Use our Paint Calculator for precise estimates. Always buy an extra quart or gallon for future touch-ups. Paint during off-season (fall/winter) when contractors offer discounts.
💡 Quick Tips
- Always prime bare drywall before painting
- Buy all paint at once to ensure color consistency
- Keep 10-15% extra for touch-ups
- Use flat paint on ceilings — it hides imperfections best
- Test paint colors on a small patch before committing
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