En Dash vs. Em Dash

What is a dash and when should we use it? A dash is a mark of separation stronger than a comma, less formal than a colon, and more relaxed than parentheses. (Bold and underlining added) *from The Elements of Style, fourth edition, by William Strunk Jr. and E. B. White, page 9

Look at this sentence: The first thing the lazy employees did when they arrived at work—besides slowly drinking their coffee—was to turn on their computers so the boss would think they were busy at work.

Look at the two dashes (—).   Is there anything else the writer could have used instead of the dashes?  It is possible for the writer to have used commas (,) instead of the dashes.   Since the writer could have used commas, why did she choose to use dashes?  That's a great question!

Why use the em dash?   In normal circumstances, other punctuation marks (commas, colons, or parentheses) should be used.  However, when you want a phrase or another part of the sentence to have extra emphasis, a dash may be used. 

Take a look at this sentence:   There are three things every repairman must have:  a screwdriver, a hammer, and a saw.  In this sentence, a colon has been used.  The writing seems to be formal.  In addition, the writing seems to NOT need any extra emphasis.

Take a look at this sentence:   The only thing Tony could do—if he could do anything at all—was to sit and wait for the test results to come in the mail.

Take a look at this sentence:  In this sentence, dashes are used because it seems informal and the clause inside the dashes needs some emphasis.  The emphasis is added in order to show that Tony could do nothing in this situation.  The writer could have used parentheses, but parentheses may have been too formal for this situation.

Em Dash An em dash is the width of the letter m, or two dashes when typed. Do not use a space before or after the dash Use an em dash sparingly in formal writing.

Em Dash In informal writing, em dashes may replace: commas, semicolons, colons, parentheses to indicate added emphasis, an interruption, or an abrupt change of thought.

Em Dash Examples: You are the friend—the only friend—who offered to help me. I pay the bills—she has all the fun. A semicolon would be used here in formal writing. I need three items at the store—dog food, vegetarian chili, and cheddar cheese. Remember, a colon would be used here in formal writing.

Em Dash Examples: My agreement with Fiona is clear—she teaches me French and I teach her German. Again, a colon would work here in formal writing. Please call my agent—Jessica Cohen—about hiring me. Parentheses or commas would work just fine here instead of the dashes.

Em Dash in Word The easiest way to enter an em dash ( — ) is to let Word do it.  Simply enter two hyphen characters between the two words you want to connect, and Word will turn the hyphens into an em dash.

En Dash An en dash, just one dash when typed, is used for periods of time when you might otherwise use to You never put a space before or after the dash Examples: The years 2001–2003     January–June

En Dash An en dash is also used in place of a hyphen when combining open compounds.   Examples: North Carolina–Virginia border     a high school–college conference

What is a Hyphen? A hyphen is used to join words and to separate syllables of a single word. Three-hundred-year-old

Any… Questions?