I was always unclear as to the proper usage of the hyphen, en dash and em dash, until I recently decided to do some research. It is very important in design to know the differences between dashes... and here is what I found:
Hyphen - The Hyphen has two main functions... to divide a word that needs to be split at the end of a line and to join a compound word. It is also used to separate numbers in a phone number.
For example:
Editor-in-chief
Use a Hyphen to di-
vide a split word.
Also important to remember that a Hyphen is different from a minus sign. Though they look the same, a minus sign will be positioned slightly lower on the type line than the Hyphen.
EnDash - The En Dash will often be used as a substitute for the word "to". It is used to separate dates, times, or to show durations. The En Dash also has a space on either side of it, and is approximately the width of the letter 'n'.
For example:
April 10 – 14, 2014
1:00 – 3:00
Em Dash - The Em Dash is used to indicate a break or interruption in thought or to separate a sentence from a bullet point. The Em Dash has no space on either side, and is approximately the width of the letter 'm'.
For example:
Real Estate websites—a place to find your dream home.
Often times these special dash characters need to be selected from hidden text menus within design or word processing programs. But now that you understand the differences between the three, you'll be sure to select the right kind of dash for your next project. I hope you find this information helpful!