Vim Word Count! (type g CTRL-g)

To get a word (and line and character) count in Vim without any external tools, just type g C-g.

That is, type g followed by CTRL-g.

Example as I type on this page right now:

Note that this also gives you the current positiion of the cursor in the file. Extremely handy. I’d always used wc as an external command (:!wc %) for this before.