Interior Paint Quantity Calculator
Gallons needed = wall area × coats / coverage (350 ft²/gal default).
Result
Paint needed
5.03 gallons
6 gallon containers to buy.
- Wall area800 ft²
- Coats2
- Coverage350 ft²/gal
- Raw gallons4.571
- With waste5.029
- Round up6
Step-by-step
- Total surface = area × coats = 800 × 2 = 1600 ft².
- Gallons = 1600 / 350 = 4.57.
- Add 10% waste, round up: 6 gallons.
How to use this calculator
- Calculate wall area (perimeter × height − doors/windows) using wall-area-for-paint.
- Enter area, coats, and coverage.
- Buy the rounded-up gallon count.
About this calculator
Interior paint coverage is typically 350-400 ft² per gallon for smooth surfaces, less for rough/textured. Two coats is standard for color changes; one coat works for same-color refresh on light colors. Always round up — running out mid-project means a return trip and possibly mismatched batch.
Frequently asked
Smooth drywall: 350-400 ft²/gal. Textured: 300-350. Rough/porous: 250-300. Primer can extend coverage on porous surfaces.
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Wall Area for Paint Calculator
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Sheets needed = wall area / sheet area (32 ft² for 4×8, 48 ft² for 4×12).
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