When you type two dashes in Word (–) that are preceded by a space, Word automatically changes the two dashes to an en dash (–). When you type two dashes that are not preceded by a space, Word automatically changes the two dashes to an em dash (—).

You can prevent Word from formatting hyphens as en and em dashes by disabling this feature. To do so in Word 2007:

  1. Within Word, click the Microsoft Office button.
  2. Click Proofing.
  3. Click AutoCorrect Options.
  4. Click the AutoFormat as you type tab.
  5. Click the Hyphens (–) with dash (–) option.
  6. Click OK.