Is it valid to use em dashes in formal writing? My teacher said it's informal to use em dashes under any circumstances, so I just wanted to make sure. I've gone through several related questions in here but there is no direct answer.

This was my sentence: 'In fact, as shown in latest statistics, 12.5% of America’s citizens are African Americans—who most of them are descendants of enslaved people—and they are all treated equally.' It was in a paragraph about slavery.

  • I think you're missing a lot of important information needed to answer the question, including: how the em dash(es) will be used, what type of formal writing, are you using a style guide. Also, linking to the questions you looked at but did not solve your problem is also important because questions need to show research effort. Please edit your question to address this.
    – Laurel
    Feb 27, 2018 at 0:32
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    It sounds odd to exclude a punctuation mark from formal writing altogether. Try asking your teacher for a style guide that backs up that assertion.
    – Lawrence
    Feb 27, 2018 at 1:27
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    The em dash is not informal. You can find plenty of examples in formal writing. Where you won't find it is in informal writing! The teacher is just criticizing your using it in a place where you could either split your sentence into two or use a different type of subordinating construction.
    – user31341
    Feb 27, 2018 at 2:18
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    So did you mean em dashes as opposed to en dashes, or just dashes in general? Feb 27, 2018 at 2:52
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    Just an aside about your aside: who most of them are sounds (at best) informal; I'd replace that phrase with most of whom are. Feb 27, 2018 at 9:07

3 Answers 3


Em dashes can be used if allowed by your style guide (but don't use them too often). For example, this is what APA says:

First, when would you use an em dash? The Publication Manual (p. 97) notes that em dashes are “used to set off an element added to amplify or to digress from the main clause.” The em dash draws a reader’s attention, partly because of the physical separation that the longer dash creates and partly because these dashes appear less frequently than hyphens and en dashes. The novelty of the em dash makes it perfect for text that you want to stand out.

An em dash might set off a phrase at the end of a sentence—like this one. Or, em dashes may set off a phrase midsentence—a technique that really draws a reader’s attention—as they do in this sentence. The text between the dashes is typically a digression or outright interruption of the main idea of the sentence. When used with care, this technique can really punctuate your point (pun intended)!

But “overuse,” notes the Publication Manual (p. 90), “weakens the flow of material.” One sentence with a phrase set off by em dashes draws the reader’s attention; but frequent interruptions of this type risk making your text seem disjointed or cumbersome.
APA Blog: Computer Editing Tip: Em Dashes

In contrast, there are also sources that advise against using the em dash in formal texts:

[E]m dashes should be avoided in formal technical information if you want your tone to be neutral and direct. Because the em dash draws attention to the content that it sets off so strongly, it adds a level of informality to the text.

If you write less formal information, such as marketing information, you can use em dashes for emphasis.
Developing Quality Technical Information: A Handbook for Writers and Editors

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    It should be noted that your second quotation seems to be about parenthetical dashes in general—not em dashes specifically. I'm not entirely sure whether Ghassan meant dashes in general or just em dashes, and the quotation seems to mean dashes in general as well. Feb 27, 2018 at 2:51

Yes, the em dash is used in formal writing.

This is more of a life lesson rather than a question of if an em dash is formal or informal. I think the real question is whether it's allowed. If your teacher says not to use it then do not use it for work that is submitted to your teacher.

As far as if an em dash can be used in formal writing, it certainly can if it is allowed (see above). I haven't had a problem with having em dashes in my manuscripts that were published in peer-reviewed journals such as "Energy and Fuels" that use the American Chemical Society Style Guide (ACSSG). In the ACSSG not only is the use of the em dash not prohibited, there is mention of how to use it and an example of a proofreader's mark for inserting an em dash. However the ACSSG states "do not use em dashes to separate phrases or nonrestrictive clauses if another form of punctuation can be used".

  • Welcome to EL&U. Please consider editing your answer to make it clearer what your answer to the original question is. Feb 27, 2018 at 2:58
  • Thanks! Edited to state that they are used in formal writing.
    – m_a_s
    Feb 27, 2018 at 3:12

Most authors are uninterested in such details. and wouldn't notice the difference if their paycheques depended on it.

Typographers need to know which dashes to use, but only for consistency.

Sub-editors are there to interpret between the two groups.

Sadly all of that is traditional and theoretical and given that today, Joe Author can send almost anything straight to print with no interference - for which traditionally read help, assistance or correction - from anyone else, every such Question is increasingly meaningless.

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