Colon vs. Dash: Quiet vs. Dramatic
Summary
Both the colon and the em dash introduce new information that explains or builds upon something that precedes it. A colon is quieter; a dash is more emphatic and dramatic.
- Intuition is important to survival: studies show that instinct can beat analytical thinking in a crisis.
- Don’t overthink it—let intuition guide you.
- We serve confectionary: cakes, cookies, cupcakes, and candy.
- I come bearing gifts—cookies and candy for everyone.
Colons and em dashes can often be used interchangeably, but the dash is a more versatile punctuation mark and therefore more informal. In formal texts, a colon is generally preferred over a dash to introduce a new clause or present a list.
- More formal: They need supplies: food, water, medicines, and blankets.
Less formal: They need supplies—food, water, medicines, and blankets.
Colons and dashes
A colon is a punctuation mark that helps explain or amplify. It directs attention to the information that follows. An em dash performs a similar function. It introduces an element that amplifies or builds upon something that precedes it.
- There was only one thing left to do—run!
- Anita loves her new job: she gets to read books for a living.
- Maya plans to travel the world—she wants to learn new languages, explore new places, and meet people she would never otherwise meet.
- We offer various services: web design, content development, marketing, and SEO.
An em dash is different from an en dash or a hyphen. While an em dash (which is the length of the lowercase letter m) sets off extra information or explains and amplifies, an en dash (the length of the lowercase letter n) helps to show a range. A hyphen, even shorter than an en dash, connects two words that convey a combined meaning.
- Em dash: I like cats—they have magic powers.
- En dash: We are open Monday–Friday.
- Hyphen: Home-cooked meals are overrated.
The functions of a colon and an em dash sometimes overlap, but not always. In this article, we discuss when to use a colon and when to use a dash.
To introduce new information
Both a colon and an em dash can be used to present information that explains or builds upon something that precedes it. The colon is gentle: it warns the reader that an explanation is coming. The em dash is stronger—it can indicate a sudden break in thought and add an element of surprise or drama to a sentence.
- We made a decision: we would take the train instead.
- That is when we made a decision—one that would have unexpected consequences.
- We also enjoyed their selection of desserts: we had the peach cobbler and the apple pie, both of which were delicious. We also enjoyed their selection of desserts—it was not a day to count calories.
- To become good at something you need just one thing: patience.
- I needed something I didn’t have—patience.
- The evidence is irrefutable: climate change is real.
- I knew it—he and Rita ate all the cookies!
Both a colon and an em dash can be used to introduce new information. Which punctuation mark to use then comes down to the writer’s preference. The more dramatic em dash is seen more often in informal and creative writing than in formal texts, where a colon is generally preferred to introduce a new clause or a series of words or phrases.
- Education is a right not a privilege: all children should have equal access to educational resources.
- Your thesis is missing two important sections: literature review and discussion.
- This is what life is about—you get from one day to the next.
- You choose—shall we go home and cook or just get some takeaway?
A spaced en dash may be used instead of an em dash. This is seen mainly in British usage and news copy.
- Don’t consider it a mistake—think of it as a lesson learned.
orDon’t consider it a mistake – think of it as a lesson learned.
In lists
Both a colon and an em dash can be used to introduce a series of elements in a sentence: a colon is quieter and gentler; a dash is louder and more dramatic.
- Maya has published three books: two novels and a biography.
A dash could be used instead in the example above and often would be in informal writing.
-
Maya has published three books—two novels and a biography.
But a dash would work better than a colon if the information presented is surprising, humorous, or in some way dramatic.
- Maya has published three books—a book on how to write books and two on how to get yourself published.
Note that you could just as well use a colon in the example above. Perhaps you want to introduce funny or surprising information but gently rather than dramatically. Which punctuation mark to use then comes down to choice. Most editors will suggest using a colon instead of a dash to introduce new information or a list in academic and formal writing, but the two punctuation marks are often interchangeable. If you want your sentence to carry a quieter tone, use a colon; to be loud and dramatic, use an em dash.
- Correct: They also have a great selection of desserts: peach cobbler, apple pie, carrot cake, gelato, and cheesecake.
orCorrect: They also have a great selection of desserts—peach cobbler, apple pie, carrot cake, gelato, and cheesecake.
- Correct: There are many beautiful countries to visit in Southeast Asia: Vietnam, Thailand, Malaysia, Indonesia, Cambodia, Laos, and Singapore.
orCorrect: There are many beautiful countries to visit in Southeast Asia—Vietnam, Thailand, Malaysia, Indonesia, Cambodia, Laos, and Singapore.
- Correct: This report documents the effects of climate change: rising temperatures, melting polar caps, extreme weather events.
orCorrect: This report documents the effects of climate change—rising temperatures, melting polar caps, extreme weather events.
Correct: We had no choice: it was time to call Mom.
In formal writing, use a colon instead of an em dash to introduce a vertical list.
-
A thesis has at least six sections:
- Abstract
- Introduction and literature review
- Methodology
- Results
- Discussion
- Conclusion
Between a noun and its explanation
Sometimes, a phrase or a series of nouns might precede an explanation. Both a colon and an em dash may be used to introduce the explanatory clause, but an em dash is more common, simply because such a structure aims to be dramatic and an em dash carries drama. The dash follows the noun or the list and explains it.
- A second chance—that is all I need.
- A good book, sunshine streaming through the window, a hot cup of tea—these are the ingredients for a perfect Sunday afternoon.
- To be truly free—is that possible?
- Bagels, buns, biscuits, cookies, cupcakes, etc.—we bake everything!
In titles and headings
A colon is generally used instead of an em dash between a title and a subtitle, particularly in formal usage, such as academic texts.
- On Silence: A Memoir
- The Sixth Extinction: An Unnatural History
- Sapiens: A Brief History of Humankind
It is not incorrect to use an em dash—a dash, after all, also explains what precedes it—but a colon is preferred. Remember that an em dash is always more dramatic than a colon, so you won’t encounter it often in the titles of serious works. An em dash (or a spaced en dash) may also serve as a secondary punctuation mark when a colon has already been used.
- The Ghost Map: The Story of London’s Most Terrifying Epidemic—and How It Changed Science, Cities, and the Modern World
- Hot, Flat, and Crowded: Why We Need a Green Revolution – and How It Can Renew America
Most style manuals, like the Chicago Manual of Style, MLA Handbook, and AP Stylebook, suggest using a colon to separate subtitle from title. The APA Publication Manual does note in its section on capitalization that the first word after a colon or dash in a subtitle should be capitalized, thus allowing for the em dash to be used in titles.
Em dash: Other uses
Em dashes can replace parentheses and commas to set off explanatory text. A colon cannot be used in this way.
- Such events offer valuable data to stakeholders seeking to mitigate such effects—or to benefit from them.
em dash in place of a comma
- Such events—floods, hurricanes, landslides—are increasing in frequency.
em dashes in place of parentheses
Use an em dash instead of a colon to indicate a sudden break in thought.
- I needed—what is it I needed?—oh yes, I needed a toothbrush.
Also use an em dash to mark an interruption.
- “Can you—”
“Of course I can!”
The em dash is a versatile punctuation mark that can be used for all sorts of purposes. It can connect, highlight, or set off information. It can also be used to punctuate dialogue, mark an interruption or aside, and set off author names in quotations.
Colon: Other uses
Use a colon instead of a dash in glossaries or lists of abbreviations to define a term.
- UFD: unidentified floating device
- wrong turn: A turn that is not right
- structured data: Data stored in a database in a standardized format
Also use a colon instead of an em dash to introduce a vertical list or a horizontal numbered list.
- We accept these forms of payment:
- credit/debit card
- check
- bank draft
- gift card
- cash in an envelope
- Remember to pack these four essentials: (1) a flashlight, (2) chocolate chip cookies, (3) a good book, and (4) an extra pair of socks.
Examples from published content
Here are some examples that show how both colons and em dashes (or spaced en dashes) introduce information that explains or builds upon something that precedes it. In all these sentences, either a colon or a dash would work. The choice of punctuation mark depends on whether the writer wants to introduce new information quietly and gently (with a colon) or loudly and dramatically (with a dash).
The principle of give and take is the principle of diplomacy—give one and take ten.
— Mark Twain, Bite-Size Twain: Wit and Wisdom from the Literary Legend (2015)We all have a tendency to think that the world must conform to our prejudices. The opposite view involves some effort of thought, and most people would die sooner than think – in fact they do so.
— Bertrand Russell, The ABC of Relativity (1925)Another belief of mine: that everyone else my age is an adult, whereas I am merely in disguise.
— Margaret Atwood, Cat’s Eye (1988)But in a long run it can also be a handicap: to wake up every morning with one’s eyes on a fresh evidence of inhumanity . . . can be limiting.
— Doris Lessing, African Stories (1965)Give it a more fascinating name: call it hope.
— Jane Austen, Sense and Sensibility (1811)They don’t mind it; it’s a regular holiday to them—all porter and skittles.
— Charles Dickens, The Pickwick Papers (1836)
Since the em dash is more versatile than the colon, it is seen more often in poetry, but each has its uses, depending on how the poet wants the lines to flow—gently or dramatically.
I wake to listen:
A far sea moves in my ear.— Sylvia Plath, “Morning Song,” Collected Poems (1960)After the novels, after the teacups, after the skirts that trail along the floor—
And this, and so much more?—
It is impossible to say just what I mean!— T.S. Eliot, “The Love Song of J. Alfred Prufrock,” Collected Poems 1909-1962 (1963)
In formal and academic writing, the colon is preferred over the em dash to introduce an explanatory clause, a list, or a series of elements.
The results confirmed our original theory: appreciating small things can make life feel more meaningful.
— Joshua Hicks and Frank Martela, “A New Dimension to a Meaningful Life,” Scientific American (April 15, 2022)We also calculate two additional forecast skill metrics: the Brier skill score (BSS) and forecast accuracy.
—Jacox et al., “Global Seasonal Forecasts of Marine Heatwaves,” Nature (April 20, 2022)
Usage guide
Both a colon and an em dash can be used to explain and amplify. The colon lends a quieter tone to a sentence: it presents new information more gently than the em dash, which is louder and more emphatic. The colon is generally preferred in academic, business, and other formal writing. An em dash is used when the information presented is surprising, humorous, or in some way dramatic. In general, remember that a dash is a more versatile punctuation mark than a colon, and thus a more informal one.