I always stumble when using abbreviations in a sentence, as they inherently contain a period in them. How do I use a comma or a semicolon after an abbreviation? How about a period?

E.g. (This is an example of my quandary)

  • This is a question of style and there's no single standard. You need to follow and conform to the applicable style guide in each case.
    – Kris
    Oct 3, 2012 at 13:11
  • So meta. Wow....
    – tox123
    Dec 29, 2015 at 21:17

5 Answers 5


Based on the "Oxford Manual of Style" I changed my approach:

  • At the end of a sentence don't add a second period.
  • For other punctuation still include the period. E.g. "IT.?" would be right.

But, when I was reading Mathematics at university I was told to always add the sentence ending period whatever went before, so if an equation ended with ellipsis there would be four periods together.

Summary: it is a matter of style.

  • 6
    A sentence-ending ellipsis doesn't (necessarily) follow the same rules as a sentence-ending abbreviation. They usually have four dots regardless. May 2, 2013 at 23:40

This pretty much explains who the period belongs to:

This one is simple enough: never double up periods. If a statement ends with “etc.” the period in the abbreviation does double duty, serving as the full stop to end the sentence. If, however, you need another mark of punctuation after an abbreviation, you can put it after the period

So, it really belongs to no one: it is shared. Your link would include the period.
N.B., emphasis added by me.

To ensure that there is only one period; taken from Wikipedia:

Abbreviations A full stop is used after some abbreviations.[3] If the abbreviation ends a declaratory sentence there is no additional full stop immediately following the full stop that ends the abbreviation (e.g., My name is Gabriel Gama, Jr.) This is called haplography. Logically there should be two full stops (one for the abbreviation, one for the sentence ending), but only one is conventionally written. In the case of an interrogative or exclamatory sentence ending with an abbreviation, a question or exclamation mark can still be added (e.g., Are you Gabriel Gama, Jr.?). [edit]

  • The first example link surely seems more natural to me, but it's a bit tricky. For example, if the next sentence started with any capitalized word (proper noun for instance), it could appear that the sentence does not end with the abbreviated word, but continues. I found an answer to this on Yahoo answers but it was decorated with "lol"s, ascii art, stickers and glitter - so I didn't trust anything about it. Thanks for the better reference, the answers to the duplicate this was closed as didn't help too much. Jun 4, 2011 at 19:50
  • @WesleyMurch: Before the invention of the Linotype, there would be no ambiguity unless a period appeared at the end of a line (something typographers would try to wrap text to avoid in any case). A sentence-ending period would be followed by a wide space; a mid-sentence abbreviation-marking period would be followed by a narrow space. I find it curious that many computer typesetting guides suggest that use of two spaces is a throwback to typewriters' limitations, when in fact the use of the same width space in both cases was a consequence of Linotypes' limitations.
    – supercat
    Sep 12, 2014 at 17:11

I would go with the "clarity rule," use the punctuation that makes the most sense and makes your meaning easiest to discern.

In practice I try to structure my sentences to avoid having to place an abbreviation at the end, where the closing period would collide with the full stop at the end of the sentence, but otherwise use the periods and punctuate the rest of the sentence as required; if the sentence structure requires a comma or semi-colon after the abbreviation then I would place it after the period.


You could avoid the problem by removing the periods (or full stops). Eg: like so. In fact, the B.B.C. has completely done away with periods in abbreviations and acronyms in its writing, as have several other publications. If you do decide to include periods within your writing, you can simply place the punctuation directly after them, unless it is a period. For instance, an abbreviation for doctor is Dr. This sentence is a new sentence, but if I was talking about a Dr. and didn't have a capital letter, it is quite obvious that it is the same sentence.

So you have at least two choices:

  1. Put punctuation after an abbreviation just as normal, except for periods.
  2. Write your abbreviations and acronyms without periods.

p.s. E.g. (exempli gratia) is also an acronym.

  • Acronyms and initialisms are types of abbreviations IMHO. Please correct me if I am wrong. Aug 13, 2010 at 12:01
  • -1, e.g. is both an acronym and an abbreviation. Like U.S. In fact, I believe all acronyms and initialisms are also abbreviations, by definition.
    – cori
    Aug 13, 2010 at 12:49
  • You punctuated BBC incorrectly ;)
    – Max Nanasy
    Aug 29, 2012 at 1:43
  • 1
    @MaxNanasy On purpose :-) Sep 6, 2012 at 5:06
  • @VincentMcNabb :O
    – Max Nanasy
    Sep 6, 2012 at 20:06


When you end a sentence with an abbreviation, you don't need an extra period. The story is different when the sentence is a question or exclamation—then you need both punctuation marks.

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