Paint Calculator
Calculate gallons of paint needed for walls, ceiling, and trim in any room
Room Dimensions
Paint Options
Enter room dimensions to see how many gallons you need
Tips & Notes
- •One gallon covers roughly 350–400 sq ft of smooth walls; 300 sq ft for textured.
- •Always prime new drywall or when making a dramatic color change.
- •Satin or eggshell finish is most practical for walls — easier to clean than flat.
- •Ceilings typically need flat/matte finish paint; most brands have a dedicated ceiling formula.
- •Buy 10% extra — it's nearly impossible to match a batch later if you run short.
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Materials & Supplies
Pro tips for paint
- ›One gallon covers roughly 350–400 sq ft of smooth walls; 300 sq ft for textured.
- ›Always prime new drywall or when making a dramatic color change.
- ›Satin or eggshell finish is most practical for walls — easier to clean than flat.
- ›Ceilings typically need flat/matte finish paint; most brands have a dedicated ceiling formula.
- ›Buy 10% extra — it's nearly impossible to match a batch later if you run short.
Frequently asked questions
How much paint do I need for a 12×12 room?▾
A 12×12 room with 8' ceilings has 384 sq ft of walls (minus ~40 sq ft for doors/windows = ~344 sq ft) plus 144 sq ft of ceiling. At 350 sq ft/gallon, one coat needs 1.4 gallons. Two coats: 2.5 gallons. Order 3 gallons to allow for touch-ups.
How many coats of paint do I need?▾
Plan on 2 coats for most projects. Add a primer coat (or self-priming paint) when changing from dark to light color, painting new drywall, or covering stains. Single coats only work when refreshing the same color over an existing finish.
What sheen of paint should I use?▾
Flat/matte: ceilings and low-traffic adult bedrooms. Eggshell: most walls — good balance of washability and softness. Satin: kids' rooms, hallways, bathrooms. Semi-gloss: trim, doors, kitchens, bathrooms. Gloss: doors and accents only.
How much does paint cost in 2026?▾
Mid-grade interior paint (Behr Premium, Sherwin Williams SuperPaint): $35–$55/gallon. Premium (Benjamin Moore Aura, Sherwin Emerald): $70–$100/gallon. Builder-grade contractor paint: $20–$35/gallon. Installed by a pro: $2–$6/sq ft of wall.
How long does one gallon of paint cover?▾
One gallon covers 350–400 sq ft on smooth walls (one coat). On textured or porous surfaces, expect 250–300 sq ft. Lighter colors over dark may need 3 coats; primers cover 200–300 sq ft because they're applied thicker.