Managing Your eBook Library with Calibre

by | May 31, 2010

Calibre, an ebook management software suite, debuted in 2008. Since then, the open source program has gained over 1.2 million users around the world. Originally authored by Kovid Goyal, it’s now supported by a large open source community.

Calibre (pronounced cali-ber) has an interesting set of functions, and I happened on it researching ebook conversion software tools. Although Calibre provides conversions from a large number of formats, it has many other functions as well, and represents an interesting direction for content management in the world of many competing ebook formats.

Six Integrated Functions to Manage Your EBooks

Calibre has an amazing conversion engine built into it. I went to Calibre’s main website and downloaded then installed the software. Calibre has a single interface from which you perform all its various functions:

  • Library management—Manages your entire library of ebooks, regardless of the ebook format of your original, including the use of metadata, tagging and long comments
  • E-book conversion—Supports a truly huge number of formats, in both directions. The conversion engine can rescale fonts, automatically detect/create book structure, and insert the book metadata into a “Book Jacket” at the start of the book
  • Synchronization—Calibre will sync your ebook library with virtually any ereader you can find
  • News fetcher—Provides access to over 300 news sources through syndication, delivering news feeds automatically to your ereader on a schedule you establish
  • E-book viewer—Calibre can open and read ebooks in virtually any format known to man
  • Content server—Sets your own computer up as your content server, making your entire library of digital books available anywhere you can connect to the internet

Test Driving The Conversion Engine

I added two different kinds of documents to Calibre’s library. One was a Word document, a simple short story. The other was the PDF version of a 300-page book I had done for a client. These were about as different as two documents could be. And the conversions that Calibre produced were also distinctly different.

In each case I added the book to the Calibre Library, then used the conversion engine to convert them each to ePub, the format used by Sony Reader, B & N Nook, and the Apple iPad. This format is also used by the Stanza ereader application, and I have the iPhone version of Stanza on my phone. It’s about the best reader for the iPhone that I’ve tried so far.

Calibre’s conversions are incredibly fast. It basically converts your text on the fly, from any format, to any format. If you try to send a book to your ereader, and the book is in the wrong format, Calibre simply converts it in the transfer process. This is the way software should work, don’t you think? After all, the computer ought to be able to make these decisions.

Here are two screen shots from Stanza on my iPhone showing the two texts and how they stood up to the journey to ePub.

ebook conversion, book design

Click to enlarge

ebook conversions book design

Click to enlarge

The first was converted from the Word file. You can see that with a clean file like this, the transition is seamless, and all is good. The second was converted from PDF. In fairness, Calibre rates PDF translations as the least desirable of all on its long list, so it’s no surprise this didn’t translate that well.

The biggest problem is the insertion of hard returns on every line, breaking the text into almost unreadable chunks.

Automatic Retrieval and Direct Editing of Metadata

Among the services provided by Calibre is direct access to the metadata records for your books, and the ability to catalog and search your collection through user-applied tags, or by standard categories like Author, Publisher, and so on.

Calibre has some impressive tricks, too. Armed with an ISBN it can go to the web and download cover art and complete data records for your ebook titles.

Do You Need It?

Calibre does an amazing job of supplying easy conversion of formats so you don’t have to worry about them. After all, if what we want to do is read books, why should we have to worry about things like Mobi and PDF and ePub? Calibre seems to me to be a step in the direction of making ebook libraries much more manageable.

For instance, it treats each book as a single entity, no matter how many formats you translate it into. That just makes sense.

calibre ebook conversion
On the downside, not all the conversions will work well, and the interface looks a lot like early Windows software I remember from the 1990s. But with the open source community behind it, and the amazing conversion, news reader, library management and omni-format viewer, Calibre is a powerful asset. User acceptance has been increasing, and this month over 200,000 people downloaded Calibre.

So here’s my question to you: Do you foresee a time when you’ll need content management software like Calibre? How do you “manage” your ebook library now?

Takeaway: The era of the ebooks is here. We’ll need new tools to manage the electronic library and the devices we use to read them. Calibre is an interesting take on these functions.

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tbd advanced publishing starter kit


  1. Kelly

    I recently found Calibre while searching for conversion information. Is there some special preparation you have to make to raw book files in Word or PDF to make them convert most effectively across the e-reader formats?

    I publish books and use LSI for POD and ebook distribution, plus I want to be able to offer all the different formats for sale on my own sites as well as through the online book sellers and Apple. Calibre looks so easy I feel like I’m missing something in the process. How do you know what a “perfect” ereader format looks like and when you’ve achieved it across the different platforms?

    • Joel Friedlander

      Hi Kelly. I don’t use Calibre for e-book conversions, so I’m not sure whether I can help out. If your books are simple as far as formatting goes, you might try Apple’s Pages. It does a good job of exporting to ePub. Many of the e-reader makers have software that allows you to see what the book will look like on the reader. For instance, if you upload a *.MOBI file to Amazon (or a simple Word file for them to convert) it will show the file in a Kindle simulator. You might also want to download the free Adobe Digital Editions e-book reader to see your work in another format.

      • Kelly

        Thanks, Joel. I’ve been experimenting with the Calibre conversion and I’ve seen a converted book through Lightning Source on the Adobe Digital Editions.

        I guess what I’m more curious, or concerned, about is to know that the final product really looks the best it could in whatever ereader format. I don’t know what it should look like in EPUB format or .MOBI format to know that it’s converted correctly. If you don’t know that how would one identify and fix a problem.

        The ones I’ve experimented with all look reasonable though most lose the bookmarks from a PDF with every chapter bookmarked and the TOC doesn’t work in the ereader format. And some show pages numbers where others don’t.

        Am I making any sense?

        • Joel Friedlander

          Sure, absolutely. There are many e-reader emulators, as I mentioned, but the best test is to load the file onto the real thing. Since I have an iPad I usually test ePub files there. But all the links in the Table of Contents should work properly, and the e-book file has to be set up properly for those to work. As you know you can’t fix the layout quite the same way, and the books look different depending on the hardware they are running on and how the user has manipulated the book by changing fonts, sizes etc. I believe iBooks shows page numbers, but some others don’t. This is partly a problem of no standards for e-books, but we have to live with it for now.

      • David bergsland

        I’ve been experimenting with using Calibre to convert my ePUBs to mobi to upload to Kindle. It seems to work well so far.

  2. Max

    People usually use Calibre to manage free e-books, and some of them may by accident be pirated. A whole library of “free” e-books is quite an evidence against you. So the only purpose to use Calibre is to convert formats.

    • Joel Friedlander


      There are hundreds of thousands of free ebooks available from Google, Gutenberg Project, Smashwords and many other vendors. I’ve used Calibre for conversions, for reading ebooks, and for managing a wide variety of formats. Thanks for your comment.



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