title_body: Which size is taken into account by Amazon when calculating the download fees I get two very different sizes for my ebook in mobi format and, before publishing it, would like to know which size is the one which is taken into account by Amazon for calculating the download fees they charge under the 70% royalties option:
  
  When compiling the file with kindlegen, I get the following sizes:
  
  Approximate Standard Mobi Deliverable file size :   0002805KB
  Approximate KF8 Deliverable file size :   0002817KB
  
  
  Now, when I look on my harddisk, I see a mobi file of 11.5MB
  
  Which is the one I'd have to pay for ?
upvoted_answer: You might find this article https://www.52novels.com/from-the-ebook-formatting-files-why-is-my-mobi-file-so-huge/ and this post to be helpful. How can I reduce the resolution of images in an epub or mobi file?
  
  From the first article: 
  
  
    Amazon understands this is unfair. After all, it prefers high-quality ebooks that play nicely with the various Kindle ereading systems.Rather than penalize authors and publishers for making beautiful full-featured ebooks, it calculates the delivery fee based on the smallest version which is usually the KF7 version. You can verify this by checking the Rights &amp; Pricing page at your KDP Bookshelf.