Ceiling Paint Calculator

How much paint does a ceiling need?

Painting a ceiling almost always uses more paint than you'd guess, because ceilings drink up that first coat and usually need a second pass for an even, shadow-free finish. This calculator keeps the math simple: it takes your ceiling's length and width, works out the square footage, and divides by a standard coverage rate of 350 square feet per gallon — then multiplies by the number of coats you plan to roll.

The formula we use

Gallons = (Length × Width) ÷ 350 × Coats. So a 12 ft × 10 ft ceiling is 120 sq ft; at two coats that's 240 sq ft of coverage, or about 0.69 gallons — meaning one gallon does the job with a little to spare. The 350 sq ft/gallon figure is a common average for flat ceiling paint on a primed, smooth surface. Rough, textured, or popcorn ceilings soak up more, so round up.

How to use it

1. Measure your ceiling's length and width in feet.
2. Type both numbers into the fields above.
3. Set how many coats you plan to apply (two is typical).
4. Read the gallons needed — results update as you type.
5. Use the "Buy" line for how many whole gallons to grab at the store.

These figures are estimates to help you plan a purchase, not a professional quote — buy a little extra for touch-ups.

FAQ

Why does it assume 350 square feet per gallon?

That's a widely used average coverage rate for a single coat of flat interior paint on a smooth, primed ceiling. Check your can's label — some premium paints claim 400 sq ft.

Should I always plan for two coats?

Yes, for most ceilings. One coat rarely hides roller marks or old stains evenly. Go to three coats if you're covering a dark color or water stains.

Do textured or popcorn ceilings need more?

They do — texture increases surface area, so add 10–20% and round your gallon count up to be safe.

What about primer?

New drywall or stained ceilings need primer first. Run the same numbers for one coat of primer, then add it to your shopping list.