📊
Paint Calculator - Gallons Needed for Room
Free paint calculator. Calculate how many gallons of paint you need for walls, rooms, and exteriors. Account for doors, windows, and coats.
Paint Calculator
Calculate paint needed for your project
Paint Needed
Enter your values to see results
and click the "Calculate" button
Paint Calculator
Calculate how much paint you need for walls. One gallon typically covers 350-400 sq ft with one coat. Always buy a little extra for touch-ups.
Paint Calculation
Wall Area = 2 × (L + W) × H - (Doors × 21) - (Windows × 15)
Coverage: ~350 sq ft per gallon. Rough/textured walls need more paint. Dark to light color changes need primer.
Frequently Asked Questions
How many coats of paint do I need?
Usually 2 coats. May need 3 coats when: covering dark colors, using bright/deep colors, or painting porous surfaces.
Do I need primer?
Use primer when: painting over dark colors, covering stains, painting new drywall, or changing between oil/latex.
Related Calculators
Explore more calculators
100+ calculators for finance, health, math, and everyday life
All Calculators