APA Abbreviations // Purdue Writing Lab

Note: This page reflects the latest version of the APA Publication Manual (i.e., APA 7), which released in October 2019. The equivalent resource for the older APA 6 style can be found here.

In APA, abbreviations should be limited to instances when a) the abbreviation is standard and will not interfere with the reader’s understanding and b) if space and repetition can be greatly avoided through abbreviation. You should not overuse abbreviations (writing is easier to understand when words are written out); you should also not underuse abbreviations (in general, if you use an abbreviation, it should appear at least three times in your paper, because fewer uses mean it is more likely your reader will forget what the abbreviation refers to).

There are a few common trends in abbreviating that you should follow when using APA, though there are always exceptions to these rules. When abbreviating a term, use the full term the first time you use it, followed immediately by the abbreviation in parentheses.

According to the American Psychological Association (APA), abbreviations are best used only when they allow for clear communication with the audience.

Exceptions: Standard abbreviations like units of measurement and states do not need to be written out. APA also allows abbreviations that appear as words in Merriam-Webster’s Collegiate Dictionary to be used without explanation (IQ, HIV, RNA, CIA, UNESCO).

Do not use periods or spaces in abbreviations of all capital letters, unless it is a proper name or refers to participants using identity-concealing labels: 

G. R. R. Martin, J. K. Rowling, F. Scott Fitzgerald, P. T. Barnum, F.I.M., S.W.F. MA, FBI, CD, URL, HTML, RSS, APA

Exceptions: Use a period when abbreviating the United States as an adjective (U.S. Air Force or U.S. President)

Use a period if the abbreviation is a Latin abbreviation or a reference abbreviation:

etc., et al., e.g., a.m. Vol. 1, p. 68, 3rd ed.

Do not use periods when abbreviating measurements:

mm, ft, lb, mi, min, kg, l

Exception: Use a period when abbreviating inch (in.) to avoid confusion.

Units of measurement and statistical abbreviations should only be abbreviated when accompanied by numerical values:

15 mg, 250 mi, M = 5.7 measured in milligrams, several miles after the exit, the means were determined

Only certain units of time should be abbreviated.

Do not abbreviate:

day, week, month, year

Do abbreviate:

hr, min, ms, ns, s

To form the plural of abbreviations, add s alone without apostrophe or italicization.

kgs., CDs, Eds.

Exception: To avoid confusion, do not add s to pluralize units of measurement (i.e., use "12 m" to signify "twelve meters," not "12 ms").

Abbreviations in Citations

Citations should be as condensed as possible, so you should know the basic rules of abbreviation endorsed by the APA to provide your readers with reference information.

Always abbreviate the first and middle names of authors, editors, etc.

White, E. B., Chomsky, N.

Use the following abbreviations within citations (take note of capitalization):

APA Citation Abbreviations
Book Part	Abbreviation
edition	ed.
revised edition	Rev. ed.
Second Edition	2nd ed.
Editor(s)	Ed. or Eds.
Translator(s)	Trans.
No date	n.d.
Page(s)	p. or pp.
Volume(s)	Vol. or Vols.
Number	No.
Part	Pt.
Technical Report	Tech. Rep.
Supplement	Suppl.