Paint Calculator
Estimate how many gallons of paint you need for your room. Automatically subtracts doors and windows.
Room Dimensions
feet
feet
feet
Subtract Openings
Paint Options
$
Results
Gallons Needed
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Total Wall Area
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Area After Subtractions
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Area to Paint (with coats)
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Paint Buying Tips
- Always buy 10% extra for touch-ups and mistakes
- Two coats are recommended for even coverage and durability
- Dark colors over light may need 3 coats; use tinted primer
- One gallon covers ~350 sq ft (32 m²) on smooth walls, less on textured
- Keep leftover paint for future touch-ups (store properly)
- Quality paint costs more but often covers better in fewer coats
Ad Space - 728x90
How to Calculate Paint
Follow these steps to figure out how much paint you need:
- Calculate wall area - Add up all wall lengths, multiply by height
- Subtract openings - Doors (~20 sq ft / 1.9 m²) and windows (~15 sq ft / 1.4 m²)
- Multiply by coats - Usually 2 coats for good coverage
- Divide by coverage - Standard is 350 sq ft per gallon
- Round up - Always round to the next whole gallon
Formula: Gallons = (Wall Area - Openings) × Coats ÷ 350