Unfortunately, Mac OS’s TextEdit hasn’t got a word count feature. However, you can add this functionality using AppleScript Editor, found under Applications, Utilities.
1. Copy and paste the following code into AppleScript Editor:
tell application "TextEdit"
set word_count to count words of document 1
set char_count to count characters of document 1
set show_words to (word_count as string) & " words. (" & (char_count as string) & " characters.)"
set dialog_title to "TextEdit Word Count"
display dialog show_words with icon 1 with title dialog_title buttons {"Ok"} default button "Ok"
end tell
2. Click Library, Scripts, Applications, and save the code in the TextEdit folder.
3. Go to the Preferences of AppleScript Editor.
4. On the General tab of the Preferences window, make sure that the Show Script Menu is selected.
5. Open any TextEdit document. Go to the Script menu and select the saved script. As a result you’ll see a dialog box showing the number of words and characters in your document.
However, if you don’t want to bother yourself with scripts, you can download NanoCount – a small app that will count words and characters in TextEdit.