title_body: How are Kindle standard pages calculated? How does Amazon Kindle count a standard page?
  
  Or, if I may ask more specifically:
  
  What is a believable range of character lengths for a standard page as calculated for Amazon Kindle?
upvoted_answer: This can be really hard to estimate without narrowing your question down a bit. 
  
  But I just measured a text-heavy book to determine: 
  
  Mobile Phone App 
  852 characters 26 lines 
  
  On a small e-ink device: 
  
  
  1217 characters ...  25 lines (3rd font size from left)
  802 characters  21 lines  (next larger size font, 2nd from left)
  
  
  Large Tablet:
  
  
  2003 characters 41 lines somewhat small font size
  1666 characters       37 lines somewhat large font size
  
  
  Users can adjust text margins and text size, so that plays a role. Also, my sample didn't have many paragraphs or line breaks. I was using a custom font on my large tablet, it seems that Bookerly is slightly smaller, so maybe add an extra 100.