How much paint for a 12×20 room with 8' ceilings?
Answer
3 gallons (2 coats)
Total wall area: 512 sq ftPaintable area (after openings): 435 sq ftCoverage needed (2 coats): 870 sq ft
Need a custom calculation?
Open the full calculator with custom inputs
How We Calculated This
Gallons = (Paintable Wall Area × Coats) / 350 sq ft per gallon
Walls: 2 × (20 + 12) × 8 = 512 sq ft. After 15% openings: 435 sq ft. × 2 coats = 870 sq ft ÷ 350 = 3 gallons
Related Calculations
How much paint for a 8×8 room with 8' ceilings?2 gallons (2 coats)How much paint for a 8×8 room with 9' ceilings?2 gallons (2 coats)How much paint for a 8×8 room with 10' ceilings?2 gallons (2 coats)How much paint for a 8×8 room with 12' ceilings?2 gallons (2 coats)How much paint for a 8×10 room with 8' ceilings?2 gallons (2 coats)
Calculated using verified formulas. Last updated March 2026.