We hop to provide the word count for LaTeX documents in OS X during our next overhaul of the usability features in the app. Getting the word count right is important (minus the latex commands) and we plan to implement it fully.

In the meantime, as a workaround one could use a tpbuild script that may be found in our github repository. Just download the script (by clicking on the 'Raw' button) and drop it in your ~/Library/Application Support/Texpad/BuildScripts directory. It relies on texcount (http://app.uio.no/ifi/texcount/) to be installed. Running the .tpbuild script from the list in the Typeset menu

will simply print the count in Texpad's log.