What are the correct ways to use a colon?
This page reflects guidance from the sixth edition of the Publication Manual.
For the most current guidelines, see the Publication Manual of the American Psychological Association (7th ed.) and our Style and Grammar Guidelines page for the seventh edition.
Use a colon
between a grammatically complete introductory clause (one that could stand as a sentence) and a final phrase or clause that illustrates, extends, or amplifies the preceding thought. If the clause following the colon is a complete sentence, it begins with a capital letter.
- Freud (1930/1961) wrote of two urges: an urge toward union with others and an egoistic urge toward happiness.
- They have agreed on the outcome: Informed participants perform better than do uninformed participants.
in ratios and proportions
- The proportion (salt:water) was 1:8.
in references between place of publication and publisher
- New York, NY: Wiley. St. Louis, MO: Mosby.
Do not use a colon
after an introduction that is not an independent clause or complete sentence.
- The formula is ri = ai + e.
(adapted from the sixth edition of the APA Publication Manual, © 2010)