Would you like to correct errors in your ePub formatted eBooks, or even split them into chapters and create a Table of Contents?  Here’s how you can with the free program Sigil.

eBooks are increasingly popular with the rise of eBook readers and reading apps on mobile devices.  We recently showed you how to convert a PDF eBook to ePub format, but as you may have noticed, sometimes the converted file had some glitches or odd formatting.  Additionally, many of the many free ePub books available online from sources like the Project Guttenberg do not include a table of contents.  Sigil is a free application for Windows, OS X, and Linux that lets you edit ePub files, so let’s look at how you can use it to improve your eBooks.

Note: Sigil took several moments to open files in our tests, and froze momentarily when we maximized the window.  Sigil is currently pre-release software in active development, so we would expect the bugs to be worked out in future versions.  As usual, only install if you’re comfortable testing pre-release software.

Getting Started

Download Sigil (link below), making sure to select the correct version for your computer.  Run the installer, and select your preferred setup language when prompted.

After a moment the installer will appear; setup as normal.

Launch Sigil when it’s finished installing.  It opens with a default blank ePub file, so you could actually start writing an eBook from scratch right here.

Edit Your ePub eBooks

Now you’re ready to edit your ePub books.  Click Open and browse to the file you want to edit.

Now you can double-click any of the HTML or XHTML files on the left sidebar and edit them just like you would in Word.

Or you can choose to view it in Code View and edit the actual HTML directly.

The sidebar also gives you access to the other parts of the ePub file, such as Images and CSS styles.

If your ePub file has a Table of Contents, you can edit it with Sigil as well.  Click Tools in the menu bar, and then select TOC Editor.  Strangely there is no way to create a new table of contents, but you can remove entries from existing one.

Convert TXT Files to ePub

Many free eBooks online, especially older, out of copyright titles, are available in plain text format.  One problem with these files is that they usually use hard returns at the end of lines, so they don’t reflow to fill your screen efficiently.

Sigil can easily convert these files to the more useful ePub format.  Open the text file in Sigil, and it will automatically reflow the text and convert it ePub.  As you can see in the screenshot below, the text in the eBook does not have hard line-breaks at the end of each line, and will be much more readable on mobile devices.

Note that Sigil may take several moments opening the book, and may even become unresponsive while analyzing it.

Now you can edit your eBook, split it into chapters, or just save it as is.  Either way, make sure to select Save as to save your book as ePub format.


As mentioned before, Sigil seems to run slow at times, especially when editing large eBooks.  But it’s still a nice solution to edit and extend your ePub eBooks, and even convert plain text eBooks to the nicer ePub format.  Now you can make your eBooks work just like you want, and read them on your favorite device!

If you feel comfortable editing HTML files, check out our article on how to edit ePub eBooks with your favorite HTML editor.


Download Sigil from GitHub

Download free ePub eBooks from Project Guttenberg

Matthew Guay
Matthew Guay is a veteran app reviewer and technology tip writer. His work has appeared on Zapier's blog, AppStorm, Envato Tuts+, and his own blog, Techinch.
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