Ebook conversion software

This section looks at desktop ebook conversion software, focusing on the two most commonly-used tools, Amazon’s KindleGen and the open source Calibre.

Ebook conversion software

Ebook conversion software does a similar job to the automated online services like Smashwords and Kindle Direct Publishing: they take a marked up source file and convert it automatically to one or more ebook formats. But instead of operating over the internet, they run locally on a PC or Mac. The two most popular programs are:

  • Calibre
  • KindleGen

Both Calibre and KindleGen have default settings that require little technical knowledge and are often good enough for personal use or in-house applications such as proofs or advance reading copies.

Beyond the ‘out-of-the-box’ default settings, both programs have extensive options for customization and fine-tuning which require a moderate to high level of technical competence.


Calibre is free software that you install on your Windows, Mac or Linux computer. You feed in a source file in a wide range of formats and Calibre outputs ebooks in EPUB, Kindle and a wide range of other formats.  It will also convert DRM-free ebooks from one format to another for use on a range of devices.

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Calibre has two levels of operation:

  • Simple. A simple, WYSIWYG (what you see is what you get) mode will quickly produce an ebook with just a few simple steps. The quick mode won’t produce an ebook suitable for commercial distribution but is fine for proof copies or internal documents. As well as its ebook conversion function, Calibre includes several other features that allow users to manage their ebook collections and sync them to e-reader devices.
  • Advanced. Calibre offers more technical operating modes to provide more control and customization. For the power user, Calibre includes features such as heuristic processing, structure detection, and batch processing, allowing a great deal of customization to improve results, including custom rules and scripts. Used effectively, these allow you to fine-tune Calibre so that it recognizes your specific document styles, mark up and structure, improving the quality of ebook outputs.

Source files. Calibre accepts input from about 20 file formats including Word (saved first as RTF – Rich text Format), HTML, PDF, EPUB and mobi.

Output formats. It outputs to a number of formats including EPUB and mobi and Amazon’s new KF8 file format (called AZW3). At the time of writing, it does not support EPUB3 format.

Calibre is supported by an active developer and user community so there is plenty of useful information and support (http://calibre-ebook.com).


KindleGen is Amazon’s advanced software tool for creating ebooks in the Kindle format. It’s a professional-grade tool which you install on your PC, Mac or Linux computer. You need a basic understanding of HTML and other technologies to use it effectively.

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Unlike Calibre, KindleGen uses an unfriendly ‘command line’ interface which will be daunting to non-technical users. However, it offers much better control over the ebook produced and error-free KindleGen output is Amazon’s ‘gold standard’ for acceptance into its catalogue.

Source files must be in HTML or EPUB. However, you can generate the required HTML file directly from Microsoft Word by using the Save As option, then selecting Web Page, Filtered for the Save as type. KindleGen’s acceptance of EPUB source files means that many publishers use EPUB as their production standard.

Output formats. KindleGen creates a single ebook file which contains both the mobi format for older Kindles and the new KF8 format.

KindleGen can be downloaded from the Tools and Resources page of the Kindle Direct Publishing site (kdp.amazon.com).

DIY example: Converting an ebook using Calibre

In our simple example, we’ll convert a Word document and a cover image that we’ve prepared using the guidelines in the previous chapter and convert it to an EPUB ebook using Calibre.

Calibre started its life as a way for early ebook users to manage their personal ebook collections and get content from sources such as websites to read on their e-readers. As a result, it’s relatively easy to use, especially if you just operate it with Calibre’s default settings and have a well-prepared source file. But there is a more technical layer which provides a powerful tool for more advanced use.

Caution: Unless you know what you’re doing, don’t use an ebook produced with Calibre for commercial distribution. Our demonstration here is for educational purposes only.

Step-by-step instructions on how to use Calibre to create an ebook

How to produce an EPUB-format ebook using Calibre.

  1. Install Calibre on your PC or Mac by downloading it from the Calibre website (http://calibre-ebook.com). The default installation is quick and straightforward.
  2. Open the Calibre program. You’ll see on the home screen a row of icons across the top of the Calibre screen. Note the four icons to the left where most of the conversion will take place: Add books, Edit metadata, Convert books, and View.
  3. Select Add books. Select your source document. Calibre will load it and it will appear in the list of titles.
  4. Highlight your document (click once on the document or the number beside it).
  5. Select Edit metadata. Calibre brings up a screen which allows you to add various details about the book including title, author, publisher and publication date. In the Comments box to the right, you can type or paste in the blurb for your book. You’ll see there are some basic formatting tools you can use to improve its appearance. In the Change cover section, click on Browse and open the cover file you’ve prepared. Click OK to return to the home screen.
  6. Highlight your document. Select Convert books. It will bring up a detailed options screen.
  7. Click OK to accept the default settings and begin the conversion. (You can change defaults from the various icons to the left but some of these options are quite technical.) On the bottom right of the Calibre screen, you’ll see a message appear, Jobs: 1 beside a spinning icon. Soon this Jobs queue changes to 0 and you’ll see a blue EPUB link appear under the cover image on the right hand side of the home screen.
  8. Highlight your ebook and select View (or click the blue EPUB link). Calibre’s own ebook viewer appears and you can view your newly-created ebook. It might not look very pretty in this viewer but it’s a simple way to review it.
  9. Select Save to disk and Calibre will save the EPUB along with any other related formats and files, to the directory you chose when you installed Calibre. Clicking on the small black triangles next to most icons will give you a range of options. For instance, you can choose just to save the EPUB file.
  10. Upload the .epub file to your e-reader. You can also let Calibre manage getting ebooks onto your ebook readers but we won’t cover these features here. Refer to the Calibre Quick Start Guide which is added to your Calibre library when Calibre is installed.

Viewing the ebooks you’ve produced

The following are useful ways to view ebooks in this production environment.

  • Calibre has its own built-in e-reader software. It’s fairly basic but it’s quick and simple to use and will allow you to view ebooks in several formats.
  • Adobe Digital Editions (ADE). For a more fully-featured e-reader application for your PC or Mac, it’s a good idea to install the free ebook reader software Adobe Digital Editions (ADE). ADE supports the EPUB format only. ADE reads ebooks in the EPUB format and is a great way to quickly review and proof your ebooks. It also reads DRM-protected commercial ebooks that have been protected using Adobe’s widely-supported Digital Rights Management system. Another useful feature: Adobe recently added the ability to print EPUB files. You can download ADE from http://www.adobe.com/products/digitaleditions.
  • Kindle Previewer. Amazon provides a free application you can use to preview your Kindle ebooks. It emulates each of the various Kindle devices.  Download Kindle Previewer


Find out more about this topic on our Digital Publishing 101 useful resources site.


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