How much paint for a 20×24 room with 12' ceilings?
Answer
6 gallons (2 coats)
Total wall area: 1,056 sq ftPaintable area (after openings): 898 sq ftCoverage needed (2 coats): 1,795 sq ft
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How We Calculated This
Gallons = (Paintable Wall Area × Coats) / 350 sq ft per gallon
Walls: 2 × (24 + 20) × 12 = 1056 sq ft. After 15% openings: 898 sq ft. × 2 coats = 1795 sq ft ÷ 350 = 6 gallons
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Calculated using verified formulas. Last updated March 2026.