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At EME, one of the problems that our academic editors encounter rather frequently in all genres of writing is confusion over the use of hyphens vis-à-vis dashes. I’d venture a guess that most writers aren’t even aware that there is a distinction between these two kinds of punctuation marks, so it’s a mistake we find ourselves correcting quite often. And if that distinction doesn’t cause enough confusion by itself, there’s also a further distinction that has to be made—between two kinds of dashes: the em-dash and the en-dash. (Minus signs, negative signs, figure dashes, 2-em dashes, and 3-em dashes all complicate the matter further, but they are of lesser importance and will be mentioned only briefly, below). Since the uses of the hyphen, the en-dash, and the em-dash are clearly distinguishable, my hope is to clear up some of the confusion here.

Hyphens [-]

The hyphen really has three main uses:

  • To separate digits (and letters) in telephone numbers, Social Security Numbers, etc.
  • To separate syllables (usually when space requires splitting a word at the end of a line of type)
  • To join two or more words together into a compound

With regard to this latter category of uses for the hyphen, it is worth noting that the current trend is toward non-hyphenation (i.e., closed compounds) wherever possible. The Chicago Manual of Style, 15th edition, §7.90 provides an extensive hyphenation guide; so does the APA Manual, 5th edition, §3.11; and so does the OWL at Purdue University [ punctuation/punct4s2.html]. Because of evolutions in usage, a current dictionary often provides the best guide for deciding when compounds should be hyphenated, when they should be written as separate words (i.e., open compounds), and when they should be written as one word (i.e., closed compounds).


one-on-one coaching

seventh-grade class

low-resolution photograph


En-dashes [–]

Longer than a hyphen but shorter than an em-dash, the en-dash is used principally in two ways:

  • In place of the word “to,” such as with ranges of dates and page numbers



pages 12–16

Genesis 1:1–2:4a

the London–Brussels train

  • To join words of equal weight (i.e., where one does not modify the other) in a compound adjective


medical–surgical procedure

the Mason–Dixon line

the New York–New Jersey border

a quasi-legislative–quasi-political decision

Although there are style sheets that direct the use of spaces before and after the en-dash, typically there are no spaces surrounding the en-dash; this allows the en-dash to be easily distinguishable from the minus sign.


 Em-dashes [—]

There are a number of uses for the em-dash, but ordinarily it represents a break in thought. Like commas and parentheses, em-dashes can be used to set off a word or phrase. There is, however, an important difference: while commas and parentheses de-emphasize the material they enclose, em-dashes emphasize the material they enclose. The em-dash may also be used to separate a subject (or set of subjects) from a pronoun, or to indicate a sudden break, an aside, or an explanatory phrase.


The way that Lisa understood it—if, indeed, she understood it at all—it was a good thing.

And that was to be the end of it—for the moment.

Be careful, however: overuse of em-dashes becomes very tedious for the reader. This is true, in part, because they involve breaks in thought; too many of them gives the reader a sense of literary hiccups as he or she tries to plough through the sentence, perhaps even losing track of what the original subject was. In part, the tediousness of overused dashes comes from the emphasis that they convey. Overemphasis functions much like using a highlighter in a book to highlight every word on the page: when everything is highlighted, nothing stands out. They are an effective tool, but should be used sparingly.

As with en-dashes, there are some style guides that suggest using spaces before and after the em-dash, but typically the em-dash is typed with no spaces before or after it (as in the examples given above).


 Minus signs, negative signs, figure dashes, 2-em dashes, and 3-em dashes

Beyond hyphens, en-dashes, and em-dashes, there are related punctuations that occur in limited circumstances and appear less frequently. Without getting into much detail, they are presented here for the sake of completeness:

  • Minus signs are typically used in equations, and are most often typed as a hyphen with a space before it and a space after it (e.g., 3 – 2 = 1). Word processing software may provide a slightly raised symbol for this purpose as well.
  • Negative signs also occur principally in equations and are typed as a hyphen with a space before it but not after it (e.g., -3 + 3 = 0).
  • Figure dashes are sometimes used in place of a hyphen between digits in numbers and codes like Social Security Numbers and telephone numbers.
  • 2-em dashes are used to indicate missing material, such as a redacted name or an expletive (e.g., Mrs. —— and Dr. —— were both opposed to the measure.).
  • 3-em dashes are used in bibliographies and reference lists to indicate that the author name is the same as in the previous entry (e.g., ———. Angels & Demons. New York: Washington Square Press, 2000).

This article is archived from the original Edits Made Easy website and is re-posted here to our new blog under a new date.