One type of change I often make in manuscripts I edit is in how hyphens, en dashes, and em dashes are used. This note will explain the differences between them and when to use each one.
What Are Hyphens, En Dashes, and Em Dashes?
Hyphens and dashes are used to separate or join things in the text: phrases, words, prefixes, numbers, etc. Visually, the difference in these punctuation marks is in their length:
- hyphen: –
- en dash: –
- em dash: —
The em dash is the width of an uppercase M. The en dash is the width of an uppercase N — half the size of the em dash. The hyphen is half the size of the en dash.
Some styles also use the 2-em dash and 3-em dash:
- 2-em dash: ——
- 3-em dash: ———
In Chicago style, these are just two or three em dashes run together, but in the AMA style manual, they appear to have a thin space between the em dashes.
When Do We Use What Dash?
If your publication venue has a style guide or a recommended style manual, there will usually be specific rules or suggestions about when to use which form of dash. As I go into the different situations below, I’ll give examples from several style manuals, including:
- Chicago Manual of Style (CMoS or Chicago)
- Associated Press (AP) Stylebook
- American Psychological Association (APA) style
- American Medical Association (AMA) Manual of Style
- IEEE style
- Modern Language Association (MLA) handbook
- New Hart’s Rules (chiefly British English)
For authors writing for self-publication, I usually suggest to picking a style you like and being consistent with it, at least within a single manuscript. If you’re working toward a book, Chicago is a good choice.
In most cases, hyphenated words and compound adjectives use the hyphen:
- long-term planning
The question of which words to hyphenate — well, that’s a whole other post.
There are exceptions to using hyphens for hyphenation: some style manuals call for the en dash to be used instead in specific situations.
Equal-Weighted Terms or Names in a Compound Adjective
APA and New Hart’s Rules use an en dash to indicate that the two terms or names in a compound adjective have an equal weight or are related to each other.
- student–teacher relationship
- Bose–Einstein condensate
In the case of multiple names, New Hart’s Rules points out that using the en dash to separate the names is useful to avoid confusing them with a single hyphenated name.
Chicago, AP, MLA, and AMA use the hyphen in these cases.
- student-teacher relationship
- Bose-Einstein condensate
Hyphenated Word Where One Side Is Hyphenated
Chicago and AMA use the en dash for hyphenation when one side of the hyphenated word is already hyphenated. Here, face-to-face is hyphenated in Merriam-Webster Unabridged, so when joining it with “meeting,“ we’d use the en dash:
- face-to-face–meeting announcement
MLA uses hyphens in this case:
- face-to-face-meeting announcement
Hyphenated Word Where One Side Is Open
Chicago and AMA use the en dash when one side of the hyphenated word is an open compound word:
- high school–level program
AP will use a hyphen but only on the last word. They note that it’s often better to reword the phrase:
- grocery store-based marketing
MLA uses hyphens between all words in the phrase, though again, it’s often better to reword it:
- high-school-level program
Hyphenation When One Side Is an Open Proper Compound Noun
Chicago, AMA, and MLA all use en dashes when adding prefixes or words to open compound proper nouns.
- post–Stone Age period
- New York–style pizza
AP uses a hyphen in this case.
- post-Stone Age period
- New York-style pizza
Chicago, APA, Journal of Finance, and IEEE use en dashes to separate number ranges
- 20–25 apples
- March 3–5, 2020
IEEE also uses en dashes to separate citation ranges:
AP and AMA use hyphens to separate number ranges:
- 20-25 apples
- March 3-5, 2020
MLA’s style guide states that hyphens can be used for number ranges in research papers (e.g., by students), but to use en dashes in published manuscripts.
Setting Aside Text
In most, if not all, American English styles, the em dash is used to set aside text from the rest of the sentence. I refer to this as a strong comma, as the em dash seems to add more emphasis to the set aside phrase or more separation from the main sentence than the comma does. The main difference between styles here is whether to add spaces around the em dash.
APA, CMoS, AMA, MLA, IEEE, and Journal of Finance do not add spaces around the em dash:
- This sentence—as short as it is—demonstrates em dashes.
AP add spaces around the em dash:
- This sentence — as short as it is — demonstrates em dashes.
Many British English and Australian English styles use en dash with spaces on either side to set aside text:
- This sentence – as short as it is – demonstrates en dashes for set aside text.
Repeated Names in Bibliographies
Chicago and MLA use the 3-em dash is used in place of author names when they are the same as the previous entry.
IEEE uses the 2-em dash for author names when they are repeated from the previous entry.
CMoS uses the 2-em dash, surrounded by spaces except before punctuation, to indicate an omitted word, often to obscure profanity or a name.
- That little —— took my money.
AMA uses the 3-em dash to indicate one or more missing words.
Omitted Portion of a Word or Name
In CMoS and AMA, the 2-em dash is used to indicate a missing part of a word or name.
- Mr. R—— said so.
New Hart’s Rules suggests using spaced en dashes to indicate missing letters in a word or name:
- Mr. R – – – said, …
How Do You Type The En Dash and Em Dash?
One problem with using these symbols is that they aren’t on standard keyboards. So, here are some ways to get them based on what tool you’re working with.
Windows and Mac Keyboard Shortcut
On Macs, you can type Option-Minus for an en dash and Shift-Option-Minus for an em dash
On Windows, it’s a bit tricker. If your keyboard has a numeric keypad, you can hold down the Alt key and type 0151 on the numeric keypad for an em dash or 0150 for an en dash. I’ve had mixed luck with this.
Windows Emoji Keyboard
Holding the Windows button and pressing period will summon the emoji menu. Pick the punctuation tab, and the en dash and em dash will be available in the General Punctuation section:
In LaTeX, two consecutive hyphens will print as an en dash, and three consecutive hyphens will print as an em dash.
Microsoft Word Insert Symbol Dialog
In Microsoft Word, go to the Insert ribbon and find the Symbol dialog.
That will open the Insert Symbol dialog. Pick the Special Characters tab, then pick the dash you want to use and click the insert key. You can also define a shortcut key for each symbol from this dialog.
Google Docs Insert Special Characters Dialog
If you’re using Google Docs, you can go to the Insert menu and choose Special Characters. This will open the Insert Special Characters dialog. Type dash in the search box, and the en dash and em dash will be on the top row.
If you’re working in HTML, typing – or – will print as an en dash, and — or — will give you an em dash.
Text Expander or Similar Tools
Getting an em dash or en dash in Windows can be tedious unless you a reliable keyboard shortcut in your program. My solution is to use Text Expander, which is one of several tools for programming keyboard macros.
I have Text Expander macros (or snippets as that program calls them) that will insert an en dash if I type
;end and an em dash if I type
;emd. For me, that’s a lot easier than trying to remember Alt-0151 or -0150, and not all of my keyboards have a numeric keypad.
That’s all for now. If you have questions about the different dashes or which to use, or if you want me to add a different style guide to this reference, feel free to ask.
- 2023-05-04: Updated to note that many Australian English styles use spaced en dashes to set off text.