Dashes are used to show a range or in place of parentheses to show that information has been inserted into a sentence. Dashes are only used in informal writing; in academic and business writing, use parentheses, commas, or colons instead. Do not put a space before or after a dash.
En Dash (–)
Use an en dash (the shorter dash symbol) to show a range of dates, numbers, or locations. In all uses of the en dash, you should be able to substitute the word “to” or “through” for the dash.
- The report covers the period 1998–1999.
- Please read pages 70–77 in your text.
- The San Diego–Las Vegas flight is on time.
Note: An en dash is slightly longer than a hyphen.
Em Dash (—)
- Indicate an interruption or an abrupt change
Use an em dash (the longer dash symbol) to indicate an interruption or an abrupt change in thought or to insert supplemental information. If the interruption or insertion comes in the middle of a sentence, add a closing dash to signal the end of the interruption.
- Last week—I think it was Wednesday—the manual was published and distributed.
- Faith, hope, and love—these virtues are very important to me.
- For emphasis
- The only exception—and it is rare—is when an extreme emergency arises.
- Set off a phrase with commas
- A solid–colored top—such as the black sweater, the brown vest, or the red shirt—would probably look best with those pants
- With quotations
- "Proper words in proper places make the true definition of a style."—Jonathan Swift