How Much Ceiling Paint Do You Need?
Enter your room size and ceiling type to get gallons and cans to buy — works for flat, textured, popcorn, and vaulted ceilings.
Last updated: May 31, 2026
Room Size (ft)
Paint Order Summary
0.8
gallons of ceiling paint
1-gallon can1
Ceiling Area144 sq ft
144 sq ft · Flat / Smooth · 2 coats
Worked Examples
12×12 Bedroom — Flat Ceiling, 2 Coats
- Area: 12 × 12 = 144 sq ft
- Flat ceiling, surface factor 1.0 → adjusted area 144 sq ft
- Paint: (144 × 2 coats) ÷ 400 sq ft/gal = 0.8 gallons → 1 can
15×20 Living Room — Flat Ceiling, 2 Coats
- Area: 15 × 20 = 300 sq ft
- Paint: (300 × 2) ÷ 400 = 1.5 gallons → 2 cans
12×12 Bathroom — Popcorn Ceiling, 2 Coats
- Area: 144 sq ft × 1.4 texture factor = 201.6 sq ft adjusted
- Paint: (201.6 × 2) ÷ 400 = 1.1 gallons → 2 cans
- Note: Popcorn absorbs 40% more paint than smooth ceilings
Ceiling Type Guide
| Type | Surface Factor | Effective Coverage | Tip |
|---|---|---|---|
| Flat / Smooth | 1.0× | 400 sq ft/gal | Standard drywall — use 3/8" nap roller |
| Textured | 1.2× | ~333 sq ft/gal | Knockdown or orange peel — use 1/2" nap roller |
| Popcorn / Acoustic | 1.4× | ~286 sq ft/gal | Heavy texture — use 3/4" to 1" nap roller, apply generously |
| Vaulted (45°) | 1.4× | ~286 sq ft/gal | Angled surface — use extension pole, work in sections |
| Cathedral | 1.5× | ~267 sq ft/gal | Steep peak — buy extra, hard to judge coverage accurately |
Frequently Asked Questions
A 12×12 ft flat ceiling (144 sq ft) with 2 coats of flat paint (400 sq ft/gal) needs about 0.8 gallons — buy 1 quart or 1-gallon can. For a popcorn ceiling, add 40% for texture absorption: about 1.1 gallons. Use this calculator and select your ceiling type for an exact count.
Textured and popcorn ceilings have more surface area than they appear — the bumps and ridges absorb significantly more paint. Flat paint on a smooth ceiling: 400 sq ft/gallon. Popcorn ceiling: effectively 286 sq ft/gallon (+40% more paint). Vaulted ceilings also add surface area due to the angle.
Two coats are standard for most ceilings. Use one coat only when touching up with the exact same paint. Use three coats when painting over a dark color, heavy stains, or bare drywall. This calculator defaults to 2 coats — adjust in the input if needed.
Primer is recommended for: new drywall (seals the surface), painting over a dark color, covering stains or water damage, and popcorn/textured ceilings that haven't been painted before. Enable primer in Advanced settings and the calculator will add primer gallons to your order.
Flat / matte is almost always the right choice for ceilings — it hides imperfections and lap marks, reduces glare from overhead lighting, and is formulated thick to minimize dripping. Eggshell works in kitchens and bathrooms where moisture resistance matters more.