The en dash (–) is slightly wider than the hyphen (-) but narrower than the em dash (—). The typical computer keyboard lacks a dedicated key for the en dash, though most word processors provide a means for its insertion.
Span or range of numbers
The en dash is used to represent a span or range of numbers, dates, or time. There should be no space between the en dash and the adjacent material. Depending on the context, the en dash is read as “to” or “through.”
The 2010–2011 season was our best yet.
You will find this material in chapters 8–12.
The professor holds office hours every Wednesday, 11:00 a.m.–1:00 p.m.
If you introduce a span or range with words such as from or between, do not use the en dash.
She served as secretary of state from 1996 to 1999.
She served as secretary of state from 1996–1999.
The regime’s most oppressive treatment occurred between 1965 and 1970.
The regime’s most oppressive treatment occurred between 1965–1970.
The en dash is used to report scores or results of contests.
The president’s nominee was confirmed by the Senate, which voted 62–38 along party lines.
UCLA beat USC 28–14 in the final game of the regular season.
Conflict or connection
The en dash can also be used between words to represent conflict, connection, or direction.
The liberal–conservative debate never ends.
The Perth–Dubai–Boston flight takes more than a day.
There is a north–south railway in the same area as the highway that runs east–west.
When a compound adjective is formed with an element that is itself an open compound or hyphenated compound, some writers replace the customary hyphen with an en dash. This is an aesthetic choice more than anything. For more on the hyphenation of compound adjectives, see here.
She is an award-winning novelist.
She is a National Book Award–winning novelist.
It was just one of many changes in this post-Obama era.
It was just one of many changes in this post–New Deal era.
They were a bunch of college-educated snobs.
They were a bunch of prep school–educated snobs.
He submitted his manuscript to a print-only publisher.
He submitted his manuscript to an e-book–only publisher.
Explanation: On its own, e-book is hyphenated. When it becomes part of a compound adjective, it remains hyphenated; the en dash is only used with the word that e-book is being compounded with.