I am self-publishing a free e-book which I make available in several formats: EPUB, online HTML, PDF.

I create (using my own programming scripts) EPUB and online HTML from XHTML sources which I write by hand (in a text editor). Then I also convert EPUB -> PDF using Calibre software.

My question: Except for PDF, which of the other file formats supported by Calibre should I publish too? (For maximum readership of my e-book, provided that some formats may be probably rare and not worth supporting.)

  • It'd be helpful to know more about the kind of book. Mainstream fiction? Academic non-fiction? A memoir? Commented Apr 14, 2013 at 23:10
  • @NeilFein: Religion.
    – porton
    Commented Apr 14, 2013 at 23:12

4 Answers 4


According to these figures, 55% of ebook buyers use the amazon kindle, regardless of their accuracy, the kindle is a very popular device. The (non-drm) format which works best with the kindle is the mobi. Pdf on the kindle is sometimes unreliable.

All other popular ereaders I know of support epub, and people on a pc will be fine with html and/or PDF.

  • 3
    PDF on a 7" device, at least, is unworkable unless you have exceptionally-good vision. In general PDF is bad for accessibility; by encoding page format you are forcing people with a display smaller than your target to scroll awkwardly. Are you sure your content is worth that trouble to your potential readers? (So aside from epub and mobi, if you're aiming for tablets, HTML will serve more users than PDF will unless you're doing small-page format.) Commented Apr 15, 2013 at 13:04

Wrong question. You don't choose the ebook format, the retailer(distributor) does.

My advice is, don't waste time creating dozens of formats. The two main ones are: Mobi for Kindle and Epub for everyone else. When you go to upload a book, the retailer will tell you which format they accept.

My only other advice is: Many retailers will say they accept MS word or PDF. Never do this, as these formats sometimes lead to formatting errors when converting. Stick to the pure ebook formats (Epub and mobi) if they allow it.


I'm not sure that this is a choice that you really have to make -- there are services that will do these conversions for you. I saw a presentation at the Digital Minds Conference 2013 by Autharium that seemed to be suitable. (I'm not associated with them, just in the general publishing software business area).


If you are self-publishing, there is no reason not to offer both EPUB and MOBI formats to ensure that the final output looks the way you want it to on the respective readers(EPUB for iOS/Nook and MOBI for Kindle). Since you have the scripts to generate these formats from your XHTML source, you are set.

If you are going to publish through one of the channels, like Amazon/etc. then you would just need to submit your EPUB or MOBI file to their specifications. Once again, since you already have the scripts to manage this, this is a one-time setup.

I would avoid PDF, as it poses many potential problems with e-readers(embedded fonts, reflow issues, and page formatting come to mind). However, once again, there is no reason why you can't offer PDF(s) for sale as well, if you are self-publishing and self-hosting the files.

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