Skip to Main Content
Go to Penn Libraries homepage   Go to Guides homepage

E-books at Penn: E-book file types

Finding and Using Ebooks at the University of Pennsylvania


Calibre logo 'ebook management"

Calibre is a multi-function ebook management tool.  In terms of file types, however, it serves a special purpose in allowing users to convert ebooks from one type to another. 

This includes the ability to convert (non-DRMed) Amazon books into other formats and vice-versa so they can be read on devices other than Kindles.  A complete list of file types that can be converted using Calibre is available.

Note: Calibre itself can't covert files of books with DRM.  However, there are Calibre plug-ins that do have that capacity and can break DRM.  This is a violation of federal law.

Standard formats

Open Standard File Types

  • Are not associated with a vendor such as Amazon, Barnes and Noble, Sony and Apple.
  • Can almost always be download onto and read on computers with current MAC or Windows operating systems.
  • EPUB is the most widely supported, vendor independent, format.  EPUB documents can be read with most vendor associated readers such as the Nook or Sony Reader as well as with independent readers such as Bluefire.  The Kindle, however, can not read .epub documents.
  • PDFs are available for many books and resources, especially those available through the Library.

Closed Standard File Types

  • Are proprietary
  • Can often only be read by one type of reader (e-books ordered on Amazon can only be read on Kindle readers and apps, for example).
  • Include Amazon's .mobi, .kf8, and .azw types, which can only be read by Amazon's Kindle readers.

Digital Rights Management File Types

  • The Adobe standard is the most frequently used.  Documents managed with Adobe DRM use the ending.acsm.
  • .acsm is not actually a file type but rather a container for a link to the item that will be viewed once the item is registered.
  • Some vendors use other file types for drm.  For instance, Microsoft Reader uses the .lit format.

Link to chart of which readers support which file types.

Penn Libraries Home Franklin Home
(215) 898-7555