Semi-Guide in Creating EPUB3 Files in Sigil

When i decided to try and create EPUB3 versions of my files, the start was not really that smooth. And even now, i'm still in the process of learning the rules.... so that i can break them later...haha.


To start with, there are plenty of guides out there for creating EPUB files... EPUB2 version, that is. And there is hardly any for EPUB3 versions. And yes, i will admit that there are videos on youtube that teaches you on how to utilize the different new features of EPUB3 such as attaching videos and audios, etc, etc,... there really isn't a definite guide in making an EPUB3 from scratch.

Which makes kinda sense, because one should be fine when one is already familiar with EPUB2, right?

Well.... not necessarily....

While the process of creating an EBOOK for an EPUB3 version is generally the same, there are some variations, which one has to take note of, to create the EPUB3 version. Especially the Table of Contents, which, for the most part, behaves a bit differently compared to EPUB2.

Now, this guide will not touch on how to add music, and videos, and such. I will only present a simple guide, but highlighting some basic but critical steps that ensures your EPUB3 file will display correctly on most current readers out there. Basically, i'm sharing what i've learned from my mistakes, so that others will know how to fix these problems when they encounter them.

And no, this is not a guide on how to create an interactive ebook. I don't think i'll be using those features for my ebooks anyway.

And before anything else, i would like to introduce a software, very much like Sigil, but with EPUB3 authoring tools.

ViewPorter EPUB3 Editor (it's free, so don't worry)

At first glance, this feels and looks like Sigil. Even the interface and menus are exactly alike. So this is more like a fork of the main program. And yes, it has additional toolbars for the new EPUB3 features for easy access. Those who are interested to use these new EPUB3 features can use this software, and play with it.

Oh, this guide will be much similar to that article i published about What are EPUBS?

And while i primarily show the steps for Sigil, if you're using another software, then find the equivalent options for that software. I will assume that it works just as well.

The Setup

Sigil is primarily an EPUB2 editor. It never enforces itself to be an EPUB3 editor. Nevertheless, this software is capable of creating and editing EPUB3.

We juuuuust need to tweak some settings in the preferences.

  • Navigate to the new General Preferences and select the default epub version you plan to work with (epub 2 or epub3) so that new empty ebooks start with the correct code.


if you plan to work with epub3 epubs, you should change your PreserveEntities setting to use ONLY NUMERIC entities. For example use & # 1 6 0 ; for non-breaking spaces and etc.


We strongly recommend enabling Mend On Open in your settings for best performance with Sigil.


Here are the few observations on the few sections of an EBOOK.


Adding a cover page for an EPUB3 is pretty much the same as of the EPUB2. You can use the hard and proper way which is using semantics. Or the easy way by selecting "TOOLS > ADD COVER" option in Sigil. Either way will work nonetheless.


There are new changes for metadata in EPUB3, but adding them is just the same for EPUB2. You can manually edit "CONTENT.OPF" and add the metadatas manually, or just go to "TOOLS > METADATA EDITOR" option in Sigil.


No changes here. Still the same as would an EPUB2. Though, you can use the new features of the EPUB3 as well (adding video, music, etc.).


The old way of adding footnotes would still work on an EPUB3. Or, you may take advantage of using pop-up footnotes for EPUB3 instead.



Disclaimer: I will not vouch on how other softwares will behave when creating TOC for EPUB3, but as far as Sigil goes, there is an additional step you have to do to complete it.


Straight up generating a Table of Contents for EPUB3 is not enough to display your ToC correctly when using different ebook readers. And it took me quite some time to realize what the problem is. (seriously, folks should have, like, proper instructions for these, instead of just warning us in the first place. And one more thing, the warning is just there, hiding in plain sight. But you're just not aware what it is and what to do about it).

Here's a snip from Sigil.

Be aware that Sigil-0.9.8 still enforces the need for epub3 to have and support an NCX so that it generates as backward a compatible epub as possible. This may be relaxed in future releases.

I basically didn't understand it the first time i read it. And it certainly didn't help when i am having trouble with it, or aware of this...methodology.

So to generate a complete TOC for EPUB3 in Sigil, there are two steps:

  1. "Generate Table of Contents" or CTRL+T.
  2. "Tools > EPUB3 Tools > Generate NAV from NCX"

That's it.

Do note that you can just do Step 1, save your work, and your EPUB3 will be fine. Only that, until you check it from different ebook readers that your Table of Contents is messed up.


Apart from the issue on Table of Contents, the rest are basically unchanged from EPUB2. And while i really like to try out those other, more popular softwares for EPUB creation like InDesign and the rest of paid softwares, their prices are just out of my range.

So there you have it.