Ceiling Paint Calculator

How to calculate paint for a ceiling

The ceiling is the easiest surface in the house to estimate, because there are no doors or windows to subtract. Measure the length and width of the room in feet and multiply them for the square footage. Then divide by the coverage on the paint can, usually 350 to 400 square feet per gallon for ceiling paint, and multiply by the number of coats. Round up to the nearest container you can buy. The PaintCare buy-right guidance recommends using 350 square feet per gallon when you do not know the exact coverage.

Two coats is the standard for a color change or a first paint job, and one coat is often enough when you are refreshing a ceiling that is already a similar color. Buying slightly more than the math says is smart, because you want a little left for touch-ups and for the inevitable second pass on a stubborn spot. Leftover paint stores for years if you seal it properly.

Worked example: a 12 by 14 bedroom

12 ft x 14 ft = 168 square feet. Two coats is 336 square feet. At 350 square feet per gallon, 336 / 350 = 0.96, so buy 1 gallon. One coat alone is 168 / 350 = 0.48 gallons, just under two quarts, but buying a gallon is usually cheaper per ounce and leaves touch-up paint. A flat white ceiling paint covers better than a gloss, which matters on a ceiling because you almost never want shine up there.

Notice how close 0.96 is to a full gallon. That is the sweet spot of a single-room ceiling, one gallon handles it with a little to spare. If the room had a dark ceiling to cover, or the paint is thin, step up to 1 1/2 gallons and keep the extra for the second coat.

Worked example: a 16 by 20 great room

16 x 20 = 320 square feet. Two coats is 640 square feet. At 350 per gallon that is 640 / 350 = 1.83 gallons, so buy 2 gallons. If the ceiling is textured, add about 20 percent: 1.83 x 1.2 = 2.2 gallons, so buy 3 gallons to be safe. Spraying instead of rolling drops coverage to roughly 200 to 250 square feet per gallon, which would push a two-coat job on this ceiling to about 3 gallons.

The great room is where the texture and the method make the biggest difference. A smooth ceiling rolled twice is 2 gallons, the same ceiling sprayed is 3, and a popcorn ceiling sprayed could be 3 to 4. Measure the ceiling, pick your coverage number honestly, and round up.

Coverage and coats at a glance

Common room sizes, figured at 350 square feet per gallon:

Ceiling paint covers about 350 to 400 square feet per gallon on a smooth surface, and textured ceilings cut that by about 20 percent. The EPA indoor air quality pages are worth a look if you are choosing a low-odor or low-VOC paint, since a ceiling is close to where you sleep.

Once the ceiling is figured, the walls are a short step away, and doing both in one trip to the store saves a second errand. Wall area is the room perimeter times the ceiling height, minus about 20 square feet for each door and 15 for each window. For a 12 by 14 room with 8 foot ceilings, the perimeter is 52 feet, so the wall area is 52 x 8 = 416 square feet, minus a door and a window, about 381 square feet of paintable wall. Add the ceiling back in and the same room totals about 549 square feet. At 350 square feet per gallon and two coats, that is roughly 3.1 gallons, or 4 gallons to buy with a little for touch-ups. Trim and doors are figured separately, usually about 1 gallon per 350 to 400 linear feet, so a typical room adds a quart or two for the trim. Keeping the ceiling and the walls on one paint list means a single order covers the whole room, and any leftover serves both for touch-ups later.

Textured ceilings, primer and dark colors

Popcorn and knockdown textures add real surface area, so plan on about 20 percent more paint than the flat dimensions suggest. A bare or patched ceiling soaks up the first coat like a sponge, so prime it first and you will use less finish paint overall. If you are covering a dark color with white, or white with a dark color, add a coat of primer or budget for a third finish coat, because two thin coats will not hide the old tone.

Water stains and smoke marks are a different problem. They bleed through ordinary ceiling paint, so seal them with a stain-blocking primer before you paint the ceiling. Skipping that step is the most common reason a fresh ceiling shows the old stain again a week later. A flat finish hides roller marks and small imperfections far better than any sheen.

Buying the right amount and storing leftovers

Buy in gallons rather than quarts when the math gets close to a full gallon, because the price per ounce drops and you will want a little for touch-ups. Keep a sealed quart on the shelf with the room written on the lid. Store the can upside down so the paint seals the rim, keep it out of freezing temperatures, and it will be good for years.

When you are done, dispose of any leftover or empty cans through a local paint-recycling program rather than the trash, since paint is a household hazardous waste in many states. For a single ceiling, the whole job is usually one to three gallons, so there is rarely much waste. Measure carefully, round up, and you will not be making a second trip to the store mid-job.

One more number to keep in mind: a single gallon of ceiling paint weighs about 10 pounds, so a three-gallon job is a 30-pound load to carry up a ladder in stages rather than all at once.