The Em Dash
The em dash is the widest dash symbol (—). The ’em’ in the name is a typographic measurement unit, historically used as a standard spacing unit in early printing. The em dash is 1em long.
An em dash can be used like a comma, a parenthesis, or a colon — it can denote basically any pause. It is different to the previously named punctuation in that it provides more emphasis, and also helps with readability. However when in place of a parenthesis or colon, an em dash can appear less formal.
Note that technically the em dash should have no surrounding spaces, though I prefer it with.
The dash can also be used to denote redaction — usually 2 for missing letters, and 3 for a full word.
E.g. A local resident, Ms. H——, claimed to have seen Mr Smith at a market in ——— just a few hours before the murder.
That being said, you shouldn’t use them too often — unless you want to sound like an LLM.
The En Dash
The en dash is half the length of an em dash (–), an ’en’ being half the width of an em.
En dashes are typically used to denote a span/range of values, or scores.
E.g. The recommended age range for this Lego product is 10–99 years old.
E.g. The Chicago Stags won with a final score of 12–7.
They are also used for:
- Representing a direction (e.g. north–west)
- Representing a conflict (e.g. the Polish–Soviet War)
- Representing a connection/relationship (e.g. the Dover–Calais Ferry)
The Hyphen
The hyphen is the shortest dash symbol (‐).
They are used to join words or to separate syllables of a word.
E.g. Hyphens are the state-of-the-art solution to any-and-all writing problems.
The Minus
The minus isn’t a dash but it looks like one (−).
Obviously a minus is used to denote mathematical subtraction, but I’d like to draw attention to the symbol.
The symbol tends to be longer than a hyphen and just slightly shorter than an en dash in most fonts.
What most people call the ‘minus’ key on a keyboard actually outputs a hyphen character. So if you want to type a minus symbol, you’ll need a character map, or something similar.
The Tilde (Honourable Mention)
The tilde is also not a dash, but I’ve included it because it looks cool (~).
The primary use case for the tilde is as a diacritic (e.g. in the Spanish ‘Ñ’).
It also has many secondary uses. Here are some of them:
- Informally to mean about/around (e.g. the trip takes ~30 minutes).
- In some languages (not English) for numerical ranges
- E.g. ‘~5’ means ‘up to 5’
- E.g. ‘5~10’ means ‘5 to 10’
- E.g. ‘10~’ means ‘10 and greater’
- In mathematics for (not exhaustively):
- Approximation (~20)
- Equivalence (x ~ y)
- Denoting same order of magnitude (x ~ 10²)
- To define a statistical distribution (x ~ B(10, 0.1))
- Geometric similarity (∆ABC ~ ∆DEF)
- \(\displaystyle{\tilde {f}}\) denotes the Fourier transform
- Median of variable (\(\displaystyle{\tilde {\mathbf {x}}}\))
- Vector quantities (\(\displaystyle {\underset {^{\sim }}{\mathbf {x} }}\))