What is an appropriate length for a Wikipedia article? This is discussed at Article length. An article can be as long as 10,000 words or more, if there are enough sources on the topic to provide for that much content. Undoubtedly there are articles that reach 20,000 words. The recommended maximum length is around 100kB of text. There is no standard for minimum length, an acceptable stub article could be as short as three or four sentences.

If you look at the menu on the right-hand side of any page on Wikipedia, there is a link to Page information. Clicking on that link shows lots of information about the page including its total size as well as how often it has been viewed. There is also this tool - you just copy and paste the text into there, and it counts it for you.