Short VS Long dash

[livetohike]

Word 2000

When I type a hyphen on the keyboard Word sometimes converts it to the
longer 'em' dash, other times it does not. I am sure it uses some
rule. What is it?

 

[Suzanne S. Barnhill]

In general, if you type two hyphens with no space before or after, they will
be converted an em dash. If you type one or two hyphens with space before or
after, they will be converted to an en dash. You can experiment to find
results with space before and not after and vice versa. None of these
conversion happens until you have finished typing the following word
(signaled by a space or punctuation).