En dashes

Use an en dash (–):

• To indicate a range of numbers, such as inclusive values, dates, or pages.
  Example
  2015–2017

• For a minus sign.
  Example
  12 – 3 = 9

• To indicate negative numbers.
  Example
  –79

Use an en dash (–) instead of a hyphen in a compound modifier when:

• One element of the modifier is an open compound.
  Examples
  Windows 10–compatible products
  dialog–type options

• Two or more of the elements are made up of hyphenated compounds (a rare occurrence).

Don’t use an en dash to indicate an empty cell in a table.

Don’t use spaces on either side of an en dash.

Exception Surround an en dash with spaces when it's used as a minus sign in an equation, in a time stamp appearing in UI, or in a date range that includes two times and two dates.
12 – 3 = 9
2:15 PM – 4:45 PM (time stamp in UI)
2:15 PM 12/1/17 – 4:45 PM 4/1/18 (range includes both time and date)

In text, don’t use an en dash in a range of times. Use to instead: 10:00 AM to 2:00 PM. In a schedule or listing, use an en dash with no spaces around it: 10:00 AM–2:00 PM.

See also Date and time term collection