Center for Academic Success

The Period

The period is used to end all sentences except those that are direct questions or exclamations. Periods are also used in abbreviations.

1. Use a period to end a declarative or imperative sentence.

• A declarative sentence makes a statement.

All is fair in love and war.

• An imperative sentence issues a request or command.

Please do not leave until you have said good-bye.

• Do not use a period if the sentence is a genuine exclamation. Use an exclamation point.

That speech was fantastic!

• Do not use a period with a sentence that asks a direct question. Use a question mark.

Will the picnic be canceled?

• However, do use a period if the sentence is a statement reporting a question indirectly.

Sara asked if the picnic would be canceled.

2. Use a period in certain abbreviations.

• The following are examples of some abbreviations which use periods:
  
  

Mr.	B.A.	e.g.	A.M. or a.m.	ft.
Mrs.	M.A.	i.e.	P.M. or p.m.	oz.
Ms.	Ph.D.	etc.	Capt.	dept.
Dr.	R.N.	Ave.	c.o.d.	P.O.

• 
  Do not use a period with U.S. Postal Service abbreviations for states.

Long Beach, CA 
Longview, TX
Detroit, MI

• Do not use a period with most abbreviated names of organizations or with commonly used abbreviations that replace words.
  
  

NATO	IRS	CSU	NBA
NAACP	TV	VCR	CD-ROM

• 
  However, sometimes usage varies, such as in the abbreviation USA or U.S.A., both of which are acceptable. When in doubt, consult a dictionary or style manual, or a publication by the agency or group in question.

• 
  If a sentence ends with a period marking an abbreviation, do not add a second period.

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