How the calculator works
It multiplies the length and width of the ceiling, multiplies by the number of coats and divides by the coverage rate for the ceiling’s surface, then adds 10% for waste.
Why texture matters
A smooth ceiling takes about as much paint as a wall of the same size. Orange peel and knockdown textures add surface area, and popcorn ceilings can take twice as much paint because the paint fills every bump and hollow. Popcorn texture also softens when wet, so roll it gently and do not overwork it.
Choosing ceiling paint
Most ceilings are painted with flat paint, which hides small flaws and does not reflect light into your eyes. Ceiling-specific paints are thicker to reduce drips and spatter. Some go on tinted and dry white, which makes missed spots easy to see.
Before you paint
In homes built before the mid-1980s, textured ceilings may contain asbestos. Have it tested before sanding, scraping or removing it.
Results are estimates. Coverage depends on the product, the tools and the wall; the rate printed on your can wins.