To the untrained eye, hyphens, en-dashes, and em-dashes all look similar, but they are used in different situations and are not interchangeable.
Here are some basic guidelines to follow:
Hyphen (-): Hyphens are mostly used to join words into compound adjectives, adverbs, and nouns. For example, “The well-known performer thrilled the audience.” They also are used to indicate a word break at the end of a line, and can be used to separate number groups, such as phone numbers (412-323-9320).
En-dash (–): An en-dash is approximately the width of the letter “N” and has two main uses. One use is to replace “through” or “to” in a range of numbers, dates, times, months, or days. With the en-dash, we can write “Monday–Friday” and “9–5.” Another use is to replace the hyphen when used with open compounds, such as “New York–based attorney” or “North Carolina–South Carolina border.”
Em-dash (—): An em-dash is twice the size of an en-dash, or roughly the width of the letter “M.” Generally speaking, they are used in informal writing to replace colons, commas, and parentheses. For example, “I follow two sports—football and hockey.” Em-dashes also can be used to indicate an interruption or a break in thought—like this—or to attribute a quote. For example: “Omaha, Omaha, Omaha!”—Peyton Manning
One other tidbit to point out involves spaces. There is some debate about whether or not there should be spaces before and after a dash. Since the spaces are really a style choice, it’s best to consult the style guide that you use, or to follow your company’s preference.
If you have a question about proper usage or can’t get your software program to cooperate, leave a comment below.