Use an en dash:
To indicate a range of numbers, such as inclusive values, dates, or pages.
For a minus sign.
12 – 3 = 9
To indicate negative numbers.
Use an en dash (–) instead of a hyphen in a compound modifier when:
One element of the modifier is an open compound.
Windows 10–compatible products
dialog box–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 or in a time stamp appearing in UI.
12 – 3 = 9
2:15 PM 12/1/16 ‒ 4:45 PM 4/1/16.
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.
Exception In a date range that includes two times and two dates, add spaces around the en dash.
2:15 AM‒4:45 PM 4/1/16 (time range on a single day)
2:15 PM 12/1/17 ‒ 4:45 PM 4/1/18 (range includes both time and date)
See also Date and time term collection