When Can I Use a Dash?

In writing, we often provide additional information that is not needed in the sentence for its meaning to be clear to the reader. That additional information is call a non-essential clause.

In this example, if you remove the non-essential clause in italics, your reader knows which person is easy to work with.

Dave, who was hired as creative director, is easy to work with.

When setting off non-essential information in the middle of a sentence, you can use commas, parentheses or dashes. Which punctuation you use is a style choice.

Em dashes tend to emphasize.

Acme Plastics — once a leader in its field — has fallen on hard economic times.

Parentheses tend to de-emphasize.

Acme Plastics (once a leader in its field) has fallen on hard economic times.

Commas tend to be neutral.

Acme Plastics, once a leader in its field, has fallen on hard economic times.

You can use dashes in other ways too:

  • to replace a colon in informal writing

Example: Ms. Prairie has all the qualities of a great teacher — a sense of humour, a knowledge of her subject and a love of her students.

  • to emphasize a word or phrase

Example: The new website is difficult to navigate — especially the search function.

What’s the Difference Between En and Em Dashes?

En and em dashes are not interchangeable.

  • Use an en dash to separate numbers and dates.
    Example: Her dates of service were 2011–2015.
     
  • Use an en dash to combine open compounds.
    Example: His sales territory extends across the Ontario–Quebec border.