How much paint for a ceiling

The short answer

A flat ceiling has the same area as the floor beneath it: multiply the room length by the width. A 12 × 10 ft bedroom has a 120 sq ft ceiling. Multiply that area by the number of coats, usually two, and divide by the coverage on the can. With a typical figure of 400 sq ft per gallon, two coats on 120 sq ft need 0.6 gallon, so one gallon is plenty. A popcorn or heavily textured ceiling soaks up far more paint, so plan on much lower coverage for that surface. The ceiling paint calculator does the arithmetic for flat and textured ceilings and suggests can sizes.

If you are painting the walls of the same room, estimate them separately with the wall paint calculator. Ceiling and wall areas are rarely the same, and many people use a different product overhead than on the walls.

How to measure a ceiling

For a rectangular room with a flat ceiling, measure the length and width of the room along the floor, wall to wall, and multiply them. Measuring at floor level is easier and safer than stretching a tape across the ceiling, and on a level ceiling the two figures match. Round to the nearest half foot; finer precision does not change how many cans you buy.

For an L-shaped room or a room with a bay, split the floor plan into rectangles, find the area of each and add them. Closets with their own ceilings count if you plan to paint them. Recessed lights, smoke detectors and small vents are too small to subtract. A large skylight well is a different story: its opening comes off the ceiling area, but its four inside faces are extra surface to paint, so measure them like small walls.

Sloped and vaulted ceilings are larger than the floor below them, because the surface is tilted. Do not use the floor area. Instead, measure along the surface of each slope from the top of the wall to the ridge or to where the slope meets a flat section, then multiply that slope length by the length of the room. Add each sloped plane and any flat section between them. A tray ceiling works the same way: measure the flat center, then add each angled or vertical step around its edge as a strip of length × height.

For more on taking measurements and keeping units consistent, see the guide to measuring walls for paint. The same habits apply overhead: sketch the ceiling, write each measurement on the sketch and add the pieces at the end.

Ceiling paint or wall paint?

Products sold as ceiling paint are normally made with a very flat, low-glare finish. Benjamin Moore, for example, describes its Waterborne Ceiling Paint as an ultra-flat finish that hides imperfections, reduces lap marks and is formulated to cut down on spatter. Those traits matter overhead: light from windows rakes across a ceiling at a low angle and shows every roller lap, and you are rolling paint above your head, so less spatter means less cleanup.

You can use flat wall paint on a ceiling, and many painters do when the ceiling and walls are the same color. Glossier sheens such as eggshell or satin are usually avoided on ceilings because they reflect light and highlight drywall seams and patches. Bathrooms are the common exception; a mildew-resistant product suited to damp rooms is the safer choice there. Whatever you choose, read the coverage on the label. Benjamin Moore lists its ceiling paint at 400 to 450 sq ft per gallon, and general guidance from Angi puts a gallon of ceiling paint at 350 to 400 sq ft for a single coat.

Paint the ceiling before the walls. Drips and roller spatter land on the walls, and the wall color can then be cut in neatly along the ceiling line.

Coverage on flat and textured ceilings

The coverage printed on a can assumes a smooth, sealed surface. A smooth drywall ceiling that has been painted before behaves close to that figure. New drywall is porous and should be primed first; the guide on when to use primer explains why and how much primer to buy.

Knockdown, orange-peel and swirl textures add surface area, and the roller has to push paint into every low spot. Popcorn (acoustic) ceilings are the extreme case. The bumpy coating has far more surface than its footprint and is absorbent, so it drinks paint. CalculatorSoup's planning figures are about 400 sq ft per gallon for smooth drywall and 350 for textured walls or ceilings, and one home-improvement guide puts a gallon at about 250 sq ft on a popcorn ceiling. Against a 400 sq ft label, that is 87.5 percent of the label figure for light texture and 62.5 percent for popcorn, which are the factors the ceiling paint calculator applies. Use a thicker roller nap that suits the texture, and expect the first coat to disappear into the surface.

Popcorn ceilings in older homes can contain asbestos. The EPA advises that asbestos-containing material in good condition that will not be disturbed is best left alone, and that if you suspect a material contains asbestos you should not touch it. Rolling paint onto a sound popcorn ceiling is gentle, but scraping, sanding or patching it is not. If the house is older and the ceiling is damaged, or you plan to repair or remove it, have it inspected by a trained, accredited professional first, as the EPA recommends before remodeling.

How many coats a ceiling needs

Plan for two coats. Angi describes at least two coats of ceiling paint as good practice, and the exact number depends on the ceiling's condition, the paint and whether you primed. One coat can be enough when you are refreshing a white ceiling with the same white and the old paint is clean and sound. Water stains, smoke marks and a color change usually need a stain-blocking primer first and then two finish coats. A popcorn ceiling may need a third pass if the first coat soaked in unevenly.

For a broader look at when one, two or three coats make sense, read how many coats of paint you need.

Worked example

Take a bedroom 12 ft long and 10 ft wide with a flat, previously painted drywall ceiling. The ceiling area is 12 × 10 = 120 sq ft. Two coats double the surface to cover: 120 × 2 = 240 sq ft. At 400 sq ft per gallon, the paint needed is 240 ÷ 400 = 0.6 gallon. The remainder is over half a gallon, so the can plan is one gallon, with 0.4 gallon left for touch-ups.

With a light knockdown texture, coverage drops to 400 × 0.875 = 350 sq ft per gallon, and two coats need 240 ÷ 350 = 0.69 gallon, which rounds to 0.7: still one gallon. If the same ceiling is popcorn, coverage drops to 400 × 0.625 = 250 sq ft per gallon, and two coats need 240 ÷ 250 = 0.96 gallon, which rounds to 1.0. One gallon covers it with nothing to spare, so if the first coat soaks in heavily, expect to pick up a quart more.

For a vaulted ceiling, take a room 12 ft wide and 16 ft long with a cathedral ceiling that rises 4.5 ft from the wall tops to a central ridge. Each slope runs 7.5 ft from wall to ridge, measured along the surface; that matches a 6 ft horizontal run and a 4.5 ft rise, because 6² + 4.5² = 36 + 20.25 = 56.25, and the square root of 56.25 is 7.5. The ceiling area is 2 × 7.5 × 16 = 240 sq ft, compared with a floor area of 12 × 16 = 192 sq ft. Two coats at 400 sq ft per gallon need 240 × 2 ÷ 400 = 1.2 gallons, which means one gallon and one quart. Enter your own dimensions in the ceiling paint calculator to repeat these steps for your room.

Sources

• Benjamin Moore, Waterborne Ceiling Paint Ultra Flat product page (coverage 400 to 450 sq ft per gallon, finish and spatter claims)
• CalculatorSoup, Paint Calculator (about 400 sq ft per gallon on smooth drywall, 350 on textured walls or ceilings)
• Angi, Ceiling Painting (coverage per gallon and number of coats)
• HomeGrail, How to Paint a Popcorn Ceiling (coverage on popcorn texture)
• US EPA, Protect Your Family from Exposures to Asbestos