Conventional Colons

Below are examples of some of the more common occasions in which a conventional colon is needed.

• Use a colon in both 12- and 24-hour time notation to indicate hours, minutes, and seconds.

6:15 a.m. 15:30 hrs elapsed time: 2:31:47

• Biblical references conventionally have a colon between chapter and verse

(John 3:16), though the MLA currently recommends using a period (John 3.16).

• When expressing a ratio, the numbers are separated by a colon.

The ratio of men to women in the Naval Reserve is 2:1.

• A colon is generally used following a salutation in a formal letter.

Dear Sir or Madam:

• Elements in memo headings need colons.

To: Dean Bardon
From: Dr. Streight
Date: March 31, 2005
Subject: A Military Writer's Handbook

• An Attention or Subject line on a letter or envelope requires a colon.

Attention: Joanne Brown

• Titles and subtitles are separated by a colon.

Shake Hands with the Devil: The Failure of Humanity in Rwanda

• In bibliographic entries, a colon separates the place of publication and the publisher.

  Bonnycastle, Stephen. In Search of Authority. 2nd ed.
       Peterborough: Broadview Press, 1996.

  Practice Exercises (12 questions)