The following post explains the difference between hyphens and dashes, helping your typography stand up to close scrutiny.
Hyphen
-
This is a short dash used to show a break in a word as it goes onto another line, or to join two words together (known as a hyphenated compound) such as “well-being”.
Hyphens are generally used as a solution for all dashing needs, which unfortunately is not always correct.
En Dash
–
/ &#ndash;
Longer than a Hyphen, the En Dash will have the same width as the uppercase N in your chosen font. You would use an En Dash instead of a comma (with a space either side) or to join two numbers together, such as in an address: 18–19 Union Road.
Em Dash
—
/ &#mdash;
This is the same width as an uppercase M. An Em Dash should be used to replace commas, semi colons, colons and brackets, to indicate emphasis, interruption or a break in thought.