Five Free “Must Use” Tech Tools for eBook Authors

by | Jun 8, 2015

By Tracy Atkins

Tracy is deep in the ebook preparation and formatting world, since he runs the operations at our e-commerce site, Book Design Templates where we sell predesigned ebook templates and provide formatting, conversion, and uploading services to authors. When he suggested an article that would help do-it-yourself authors by pointing them to free tech tools, I jumped at the chance to bring you this information.

Here’s Tracy’s rundown along with where to find each tool, how much you’ll need to tackle to learn to use it, and some notes from Tracy about real-world application of these tools.

Have fun!

Tool #1: IDPF ePub Validator – Checks your ePub for errors and reports

Where to find it:

Learning Curve: Walk in the park

Ebook tech tools

The International Digital Publishing Forum sets the standards for the ePub file specifications. Some major eBook/ePub vendors require that a submission to their service be 100% error free, and conform to the industry standards for ePub validation. (Notable examples are Ingram Spark and Smashwords, where others like Amazon KDP are much more forgiving.) In effect, the files must not contain anything that is out of spec for the format, or improperly coded for these publishers to accept the files.

Though ePub conversion from most applications is flawless, sometimes things don’t encode just right. A font may be embedded that shouldn’t be, a special character might be in the manuscript, or you might have an image that is set to word-wrap that just isn’t working.

No matter the issue, the ePub validator website will take your file, scan it, and give you a fairly detailed, if not technical, overview of what went wrong. This will allow you to fix the issue in your source interior file, be it Word or InDesign, or use another tool like Calibre or Sigil. It is as easy to use as simply uploading the file and pressing validate, and you will know that your file is ready for primetime before you try to submit it to a vendor.

Tool #2: Calibre eBook Management – Easy to use converter for eBook formats

Where to find it:

Learning Curve: A stroll

Ebook tech tools

Calibre has become one of the most widely used and beloved eBook conversion applications around due to its simplicity and robust feature set. Calibre really excels at taking books created in Word and making great looking ePub or mobi versions of the file for use just about anywhere. With only a few clicks, you can convert your formatted interior to eBook format.

(Here is a video of me doing this in minutes: It also catalogs and stores all of the files you work with on its main menu, so you can keep track of each book and it’s source files right in one spot.

Calibre also has a bunch of other great features built in too. You can easily edit the meta-date for your eBook, like the title, author, copyright information, etc., right in the console. You can also add or change the cover to your eBook with little fuss.   Calibre also includes an eBook reader, which is handy for doing quick re-work previews. Overall, it is a really easy to use package that takes little effort to achieve a great result.

Tool #3: Adobe Digital Editions – eReader for ePub files

Where to find it:

Learning Curve: Easy slopes

Ebook tech tools

Adobe Digital Editions is one of those no-brainer tools that many people need, but just don’t have. Simply put, Adobe Digital Editions is to ePub, what Adobe Acrobat Reader is to PDF. It is a very simple to use tool that lets you open up ePub files and read them, right on the screen of your computer.

The simplicity of using it is stunning, just open the file and start reading. Best yet, it is one of the most stable and consistent eReader applications around, and it is totally free.

Tool #4: GIMP – Free Photo and Image Editor

Where to find it:

Learning Curve: A moderate climb

Ebook tech tools

Making an eBook full of pictures can be pretty tough. Sizing the photos just right, making sure they are in JPG format so they are small enough to not eat into profits. Heck, just getting the colors to balance and cropping a photo can be a bear.

Like Photoshop, GIMP (GNU Image Manipulation Program) is a photo editing package for the PC and Mac. Unlike Photoshop, it’s free.

It really works great for simple tasks, like cropping and resizing photos, as well as making more complicated adjustments like editing colors, hues, and lighting. The interface is a little daunting at first glance, earning it a “medium” for ease of use, but after spending twenty minutes using it; it becomes second nature to operate.

As a free application, GIMP is pleasant and will do solid work. The basic editing tools are very self-explanatory and are easy to navigate even for a novice. If you have the means to purchase Adobe PhotoShop or Corel PaintShop Pro, and the time to learn them, by all means go that route. They have many more advanced features and filters.

However, if you just need to touch up some photos, or even resize fifty of them for your eBook, GIMP is a great option. Because of it’s popularity, there are many great help articles on GIMP out there on the web too, so you can learn more about it or get support with ease.

Tool #5: Sigil – ePub Code Editor

Where to find it:

Learning Curve: Steep

Ebook tech tools

If you have a copy of the book “Microsoft Visual Studio 2015 Unleashed (3rd Edition)” on your desk, you will find that Sigil is an easy to use tool for correcting ePub issues at the XML level. If you are fairly new to the whole “programming thing”, then Sigil is not right for you. Created as a really in-depth tool for eBook creators, programmers, and developers, Sigil lets you open up an ePub file and look at the raw computer coding that makes up and eBook and edit it right on the spot.

As an advanced tool, it is unbeatable, allowing you to quickly and easily find and change coding inside the file without having to re-convert from a source file. Intermediate users can also get some utility out of Sigil, especially when you are trying to hunt down error messages found in the IDPF ePub Validator mentioned in this article. So, it’s not for everyone, but for those that need it, it is absolutely essential.

Well, that’s my list, but I’m curious what free tools you use to work on your ebooks. Let me know in the comments!

Tracy R. AtkinsTracy R. Atkins has been a career technology aficionado since he was young. At the age of eighteen he played a critical role in an internet startup, cutting his tech-teeth during the dot-com boom. He is also a passionate writer whose stories intertwine technology with exploration of the human condition. Tracy is the self-published author of the novel Aeternum Ray and the co-founder of

Photo credit: Tellessa Myles via photopin (license)

tbd advanced publishing starter kit


  1. Adam

    Very useful. But it’s a shame Kotobee Author isn’t on the list.

  2. Noel Sadili Morado

    I’m not an author but a VA for an indie publishing firm. I usually use Adobe InDesign for layouting and Calibre/Sigil for conversion into epub/mobi… and run the epub validator to check for any error. I wish there’s a software that can streamline the process from formatting to conversion and eventually published digitally.

  3. Florent Bouillet

    Dear Tracy,
    After years of self-publishing ebooks for Apple iBooks, Kindle, Kobo, Sony, Nook Press, etc. I decided to create the simplest online tool to create beautiful ebooks. We have just launched ebook leap – we would love for you to give it a try (it’s free to try) and share any feedback you have with us.
    ebook leap makes it easy to insert pictures or illustrations and choose from a library of paragraph and chapter ornaments, allowing you to make a unique ebook. In just minutes, you can create an ebook that is ready to publish in every store. The files generated on ebook leap comply with all platforms, meaning your ebook will publish beautifully on Amazon Kindle, Apple iBooks, Kobo, Nook Press and other platforms.
    We are looking forward to hearing from you!

  4. caral from SoCal

    I am just tip-toeing up to the brink of epub, kindle…whatever and all digital formats that are out there. We just re-published (this time self-published) our books…and are desperate to figure out the kindle/pdf/epub thing. I think I need a manual. Like…really. What format errors? How do you know? I guess I need the very basics. Any thoughts?

    (I don’t even use a kindle – but I am oh-so-aware that my customers do!)
    Help! Thank you for any direction in which you might point me!

    • Tracy Atkins

      Hey Caral!

      I highly recommend our templates for Word. They make formatting an eBook really easy, and we include instructions for creating the ebook files using calibre too. Check them out at

  5. jazz singh

    thank you

  6. Mary Pax

    I use Sigil++ and the Kindle previewer to convert my epubs to mobi files. I use a paid program to create my epubs.

    I used, also free, and a great graphics program.

  7. Ken Lundquist

    I use Calibre and Sigil regularly, but for image editing I still have a copy of JASC PaintShop Pro 8.1 – prior to Corel’s purchase of the software from JASC.
    Scrivener is a fabulous writing tool and can directly export to a variety of formats; PDF, E-Pub, Mobi, Doc, ODT among others.

  8. Roland

    Great post! I copy my Word document in my HTML editor Microsoft Expression Web for full control of the layout with CSS and then convert the HTML with sigil into epubs. Sigil is is a really useful tool to create epubs, but maybe more a tool for advanced users with HTML knowledge.

    • Tracy Atkins

      I really like Expression Web for website development and work myself. MS really hit a home run with it, considering that it evolved from the much more mundane “Front Page” app. It is a bit technical for sure, and for serious pros that are great at coding, I agree that it has a beloved place. For really advanced layout and design, Adobe InDesign makes some killer eBooks too, with a great WYSIWYG interface, and lots of options.

  9. Philippe Roy

    Use Jutoh. Then, number 1,2 and 5 are covered. Better covered.

    • Tracy Atkins

      Hey Philippe!

      Jutoh looks pretty nice. Though it’s not free, it looks like something that I would like to try out and evaluate personally. Heck, it might make a good follow-up review post in the future. Thank you for suggesting it.

      • Philippe Roy

        I think it’s free now. Maybe because I bought it some years ago (worth every penny), but I think not.

      • Mary Pax

        Jutoh is nice. I use it. It’s not free, but worth it.

    • C.K. MacLeod

      Jutoh is my favourite ebook editor, particularly because it does a great job of circumventing line spacing and word spacing quirks that you find in some ebooks. It can take a bit of getting used to, so I use this cheatsheet to help me get around in Jutoh.

      • C.K. MacLeod

        Forgot to say… Jutoh will allow you to create mobi ebook files for Kindle and epub files for everyone else.

  10. Frances Caballo

    Tracy: I love this post. I’d never heard of any of these apps before. I usually pay someone to convert my manuscript to an eBook. So you’re saying that I can do it myself using this apps, right? That would be so cool!

    • Tracy Atkins

      Thanks Frances!

      You certainly can convert to eBook using the tools here. All of them are great for DIY in various capacities. The real key to success is to make sure you have a good source document or template to layout the book in and follow all of the conventions that go with formatting out an eBook prior to conversion. (A cleanly formatted file goes in; a well formatted ePub comes out.) So the conversion process is fairly straight forward in Calibre if you have all of the formatting bases covered going in. Then it becomes a matter of error checking using the validator, and correcting any issues using the other tools.



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