Thanks. I have a Mac (macOS 10.11.6). There is a folder in ~/Library/Application Support/com.evernote.Evernote, but it is hard to tell from the filenames exactly what is content, what is metadata, and what is duplicated. The entire forlder is about 300MB, so that is an approximate upper bound, assuming Evernote is not keeping some things elsewhere. Ideally the app would just tell you how much space you are using on EN's cloud servers. They seem to go out of the way to obscure the information.
I am trying to find out how much total storage space my Evernote account is using. For some reason, it does not appear in any profile, statistics, etc., lists. You would think this would be easy to find but I have looked in every conceivable place, and even searched the support database.