Paint Coverage Calculator for Interior and Exterior Projects
Accurate paint calculations save time, money, and prevent the frustration of running out of paint mid-project. Our free paint calculator helps homeowners, contractors, and DIY enthusiasts determine exactly how many gallons are needed for any painting project.
Understanding Paint Coverage
Paint coverage varies based on several factors. The quality of paint, surface texture, application method, and color all affect how far a gallon will go. Our calculator accounts for these variables with different coverage rate options.
How to Calculate Paint Needed
To calculate paint requirements:
- Measure room perimeter (length + width × 2)
- Multiply by ceiling height for gross wall area
- Subtract area of doors and windows (typically 20 sq ft per door, 15 sq ft per window)
- Multiply by number of coats needed
- Divide by paint coverage rate (usually 350 sq ft/gallon)
- Round up to whole gallons
Factors Affecting Paint Coverage
- Surface texture: Rough surfaces absorb more paint than smooth ones
- Color change: Dark to light requires primer + more coats
- Paint quality: Premium paints have better coverage and hide
- Application method: Spraying uses more paint than rolling
- Sporus surfaces: Drywall primer or new drywall needs more paint
Paint Cost Considerations
Paint costs vary significantly by quality:
- Economy: $15-25 per gallon
- Standard: $25-40 per gallon
- Premium: $40-65 per gallon
- Designer/Specialty: $65+ per gallon
Don't forget additional supplies: primer ($15-30), brushes, rollers, tape, drop cloths, and cleaning supplies can add $50-100 to your total project cost.