Hyphens and dashes in WordPress

I’ve often been uncertain about what WordPress does with one or more hyphens in various contexts, and even looking at the code of wptexturize is that useful — not all code is poetry.

One or more hyphens can produce a single hyphen (-), an en dash (–) or an em dash (—), but it’s not entirely straightforward.

TL;DR

A single hyphen becomes an en-dash if surrounded by spaces. Otherwise, it remains a hyphen.

Double hyphens become an em-dash if surrounded by spaces. Otherwise, they become an en-dash.

Triple hyphens always become an em-dash.

Common usage

Number ranges with en-dashes require double hyphens, as in 5–6. Otherwise, you’ll get a hyphen, like 5-6.

Em-dashes used as punctuation—normally without any spaces around—need to be entered as triple hyphens. If used with spaces around — which is not the common usage, however — double or triple hyphens work the same.

See — for example — How to Use Em Dashes (—), En Dashes (–), and Hyphens (-) on Merriam-Webster.

Test tables

Single hyphens

Input	Output	Result	Note
-	–	en dash	alone
word-word	word-word	hyphen	surrounded by letters
word - word	word – word	en dash	between words with spaces
word- word	word- word	hyphen	space after
word -word	word -word	hyphen	space before
5-5	5-5	hyphen	between digits
5 - 5	5 – 5	en dash	between digits with spaces

Double hyphens

Input	Output	Result	Note
--	—	em dash	alone
word--word	word–word	en dash	surrounded by letters
word -- word	word — word	em dash	between words with spaces
word-- word	word– word	en dash	space after
word --word	word –word	en dash	space before
5--5	5–5	en dash	between digits
5 -- 5	5 — 5	em dash	between digits with spaces

Triple hyphens

Input	Output	Result	Note
---	—	em dash	alone
word---word	word—word	em dash	surrounded by letters
word --- word	word — word	em dash	between words with spaces
5---5	5—5	em dash	between digits
5 --- 5	5 — 5	em dash	between digits with spaces