Paint Calculator for a Ceiling
Estimate gallons of paint for any ceiling.
Use this free paint calculator to estimate how many gallons of paint you need for any room. It calculates paintable wall area from the room dimensions, subtracts doors and windows, accounts for the number of coats, and uses a coverage rate of 350 ft² per gallon.
Gallons
1.81
Buy the next whole gallon
Paintable area
316 ft²
Total wall area
352 ft²
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Recommended tools & materials
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Paint Roller Kit
Roller, tray and covers in one set
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Angled Sash Brush
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Painter's Tape
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Canvas Drop Cloth
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How does the paint calculator work?
Wall area is the room perimeter × ceiling height. Subtract roughly 21 ft² per door and 15 ft² per average window, then multiply by the number of coats and divide by 350 ft²/gallon.
Formula: gallons = ((2(L+W) × H − doors×21 − windows×15) × coats) ÷ 350
What else do people ask about this calculator?
How much paint for a 15x20 ceiling?
A 15×20 ft ceiling is 300 sq ft. That's under 1 gallon for a single coat or about 1.5 gallons for two coats. Buy a full 2 gallons so you have enough for the second coat plus touch-ups.
Should I use ceiling paint or wall paint?
Use dedicated ceiling paint. It's formulated to drip less, hide roller marks and dry to a dead-flat finish that hides imperfections better than wall paint.
How much paint do I need for a 12×12 room?
A 12×12 room with 8 ft ceilings, 1 door and 1 window needs about 2 gallons for two coats.
How much does a gallon of paint cover?
About 350 ft² per gallon on smooth interior walls. Textured or porous surfaces reduce coverage to 250–300 ft².
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Where can I learn more about these materials?
Weights, coverage, types and buying tips for the materials this calculator estimates.
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