title_body: How does the Kindle's reading rate algorithm work?
upvoted_answer: Basically, they have no limit on how fast someone could actually read (supporting speed readers) but they do have a limit on how slow someone can read. That is, if someone takes 30 seconds to read a page, they will add that to their calculations, but if someone takes 5 minutes to read a page but only 20 seconds to read other pages then ignore the 5 minute exception.
  
  This is not surprising since people will often put a book (electronic or paper) down while they do something else, then return to it. For this reason, they really need a maximum time per page.
  
  As far as different books requiring different estimates, different books have different readability levels. If I read a book on leadership, I tend to read it quite quickly because I've already digested so much content on the topic. However, when I read a book on coding neural networks, I read much more slowly. My slowness on complex topics which I have little experience with does not mean that I am slower at reading other books/topics.