Ceilings are prone to various kinds of damage. Water seepage, cracking, staining or peeling all can make your white ceiling look rather shabby. If you have repaired your ceiling and need to touch up the paint, or if you want to repaint a section of it for another reason, you need to match the existing ceiling color. This isn't a problem if you have the original paint can – but if not, you still can find the right color. Most paint manufacturers produce similar shades of white paint, so you should be able to match yours with ease.
Collect a variety of white paint swatches from a paint or home improvement store. Don't worry about the brand. Choose swatches that you think will best match your ceiling.
Use the step stool or ladder to place the swatches against the ceiling. Do this when the room is bright. Use swatch samples for pre-mixed colors (rather than custom) first as they are the most likely to have been used on the ceiling.
Mark the swatches that look very close to the existing ceiling paint. Most likely there will be a match – but if you have more than one, mark all possible matches.
Obtain samples from the paint store for your match or matches.
Use a paintbrush to paint a square from each sample on the ceiling. Wash the paintbrush between samples or use different ones for each so you don't mix the whites. Wait for the paint to dry. Paint darkens slightly as it dries.
Examine your sample (or samples) to verify your match.
Check the finish on your ceiling. Most ceilings are painted with a flat, matte. In areas where water or steam might touch the ceiling, like a kitchen or bathroom, the finish may be semi-gloss. Eggshell and enamel finishes are less frequent. If you are unsure of the finish, pick up a swatch of finish samples at your paint store to check.