En, Em, Eh, What?

There are different types of dashes: hyphen, en dash, and em dash. What is the difference between them?

Hyphen (-): This is the width of one digit. It is used to hyphenate words that break across a new line, or to join compound words. Ex. My, this professor is long-winded.

En Dash (–): This is the width of the letter 'n'. It is used to indicate a range of values. Ex. I will be on vacation from November 6–10.

Em Dash (—): This is the width of the letter 'w'. This is used to indicate a break in thought. Ex. I was eating pizza—and what a good pizza it was—with all my favorite toppings.

Using courier font we can get a better idea of the widths:

0 n m

- – —

[Sources: Fonts.com and Wikipedia]