En Dash vs Em Dash: When to Use – and —

Two small horizontal lines. One slightly longer than the other. The en dash and em dash are among the most misused punctuation marks in English writing, yet mastering them instantly elevates the quality of any text — whether you're writing prose, building a website, or marking up technical documentation.

This guide cuts through the confusion with concrete rules, side-by-side comparisons, and every typing shortcut you'll need.

The Core Difference at a Glance

The names are typographic measurements: an en dash is traditionally as wide as the capital letter N; an em dash as wide as the capital letter M. In practice, exact widths vary by font, but em dashes are always noticeably longer than en dashes.

When to Use the En Dash (–)

The en dash has three primary jobs in standard typographic usage.

1. Ranges of Numbers and Dates

Use an en dash to express a range — a span from one value to another. The en dash replaces the word "to" or "through."

Pages 12–34
The 1939–1945 war
Open Monday–Friday, 9:00–17:00

A critical rule: never mix an en dash range with the word "from." Write either "from 1939 to 1945" or "1939–1945" — never "from 1939–1945."

2. Compound Adjectives with Multi-Word Elements

When one or both parts of a compound modifier is itself a multi-word phrase, use an en dash instead of a hyphen.

A New York–based designer
The London–Paris train route
Post–World War II architecture

A hyphen would be ambiguous here — "New York-based" might be read as "New York-based" where "York-based" is the compound. The en dash signals that "New York" is a single unit.

3. Scores and Connections

The en dash also appears in scores and votes to show opposition or connection between two entities.

The final score was 3–1.
The motion passed 7–2.
The Chicago–Milwaukee route

When to Use the Em Dash (—)

The em dash is more dramatic punctuation — it creates emphasis, interruption, and digression. It replaces several other punctuation marks in specific contexts.

1. Parenthetical Emphasis

An em dash pair (like parentheses, but stronger) sets off an aside within a sentence with more emphasis than parentheses would provide.

The solution—surprisingly elegant—took only three lines of code.
Her argument—and it was a compelling one—rested on a single assumption.

Parentheses whisper; em dashes shout. Choose based on how much you want to emphasize the interruption.

2. Abrupt Breaks and Interruption

In dialogue and narrative, an em dash signals an abrupt break or interruption mid-sentence.

"I was about to explain—"
"No," she interrupted. "I already know."

3. Introducing a Summary or Elaboration

An em dash can introduce a list or elaboration that summarizes what came before, particularly when a colon would feel too formal.

Reliability, speed, simplicity—these are the qualities we optimized for.
She had only one goal—to finish before the deadline.

4. Attribution in Quotations

In some style guides (particularly American usage), an em dash precedes the attribution of a pull quote.

"Design is not just what it looks like. Design is how it works."
—Steve Jobs

Spacing: The Great Debate

One significant stylistic divide concerns whether to add spaces around em dashes.

American English (no spaces):

She waited—and waited—for a response.

British English and some style guides (spaces):

She waited — and waited — for a response.

En dashes used as parenthetical markers in British style also use spaces:

The result – which surprised everyone – was a draw.

Pick one style and apply it consistently throughout a document or site.

How to Type En Dash and Em Dash

Mac

Windows

In Microsoft Word, typing word--word (hyphen-minus twice, no spaces) auto-converts to an en dash; word---word produces an em dash. This behavior can be controlled in AutoCorrect settings.

Linux

Alternatively, configure a Compose key and use Compose - - for en dash and Compose - - - for em dash.

HTML

<!-- En dash -->
&ndash;
&#8211;
&#x2013;

<!-- Em dash -->
&mdash;
&#8212;
&#x2014;

For proper semantic HTML, consider wrapping dashes in appropriate punctuation roles. When used as a range, the en dash needs no special markup. When used parenthetically, it's purely presentational.

CSS Considerations

When you need to generate dashes in CSS content property (for pseudo-elements or list markers), use the Unicode escape:

/* En dash as a list bullet */
li::before {
  content: "\2013\00A0"; /* en dash + non-breaking space */
}

/* Em dash for pull quote attribution */
blockquote footer::before {
  content: "\2014\00A0"; /* em dash + non-breaking space */
}

For preventing unwanted line breaks around dashes (particularly en dashes in ranges), you may want to use white-space: nowrap on the parent container or insert the non-breaking character   (narrow no-break space) around the dash.

Common Mistakes and How to Fix Them

Mistake 1: Using hyphen-minus for everything

The hyphen-minus (-, U+002D) is a typewriter holdover that serves three separate typographic roles by default: hyphen (in compound words), minus sign (in math), and rough stand-in for en and em dashes. In polished typography, each role deserves its own character.

Mistake 2: Doubled hyphens as em dash

Legacy manuscripts used -- for em dash because typewriters lacked the character. This practice persists in some technical writing communities, but HTML and modern typesetting support the actual character. Prefer — over --.

Mistake 3: Using em dash in numeric ranges

A range like "pages 10—25" uses the wrong dash. Ranges always take an en dash: "pages 10–25."

Mistake 4: Inconsistent spacing

Mixing spaced and unspaced dashes within the same document creates visual inconsistency. Establish a style rule early and enforce it with a linter or style guide.

Detecting Dashes Programmatically

If you're building a content processing pipeline, knowing the Unicode code points matters. Use our Character Analyzer to inspect any text and identify which dash character was actually used.

In JavaScript, you can test for dash characters:

const EN_DASH = '\u2013';
const EM_DASH = '\u2014';
const HYPHEN_MINUS = '\u002D';

function detectDash(char) {
  if (char === EN_DASH) return 'en dash';
  if (char === EM_DASH) return 'em dash';
  if (char === HYPHEN_MINUS) return 'hyphen-minus';
  return 'other';
}

In Python:

import unicodedata

def describe_char(char):
    return unicodedata.name(char, 'UNKNOWN')

describe_char('–')  # 'EN DASH'
describe_char('—')  # 'EM DASH'
describe_char('-')  # 'HYPHEN-MINUS'

Quick Reference Card

Style Guide Positions

Different authorities take slightly different stances on dash usage:

• Chicago Manual of Style: Em dashes without spaces (American style); en dashes for ranges.
• AP Stylebook: Discourages em dashes in journalism; favors commas and parentheses instead.
• British style (Oxford, Guardian): Spaced en dashes for parenthetical asides; no em dashes.
• CSS/HTML specifications: No prescriptive guidance; reflects content author intent.

Knowing which audience you're writing for helps determine which style guide to follow.

Next in Series: Smart quotes vs straight quotes — the invisible difference that separates polished typography from typewriter-era text. See Curly Quotes vs Straight Quotes.