Ebook Formats: A Quick Guide For Self-Publishers

Are you considering self-publishing your own ebook? If yes, then ebook formats are important and this is article is all for you. If no, well this post is probably a waste of your time and it’s best you stop reading now…

Still with me?


OK – let’s just define Self-Publish a little more clearly.

This article is for writers who intend to sell their book in ebook formats.

In short this means via Amazon or Apple onto eReaders such as the Kindle or iPad.

The goal of this article is to explain a little about the technical aspects of creating ebooks.

It’s not a full-blown technical guide.

It has been written to give you just enough information to be dangerous.

In other words, this article will help you decide on the next step forward.

By this I mean this article will give you enough information for you to make an informed choice about the best way to convert your Word/Pages/OpenOffice file into an ebook.

HINT – There’s more than one type of ebook format and not all eReaders will read each type.

Think VHS vs Betamax

What Are The Key Concepts Behind Ebook Formats?

Let’s start at the start…

Ebooks are very different from documents created on word processors such as Office, Pages and OpenOffice.

At the most basic level documents created by word processors have the text and style mixed together.

This means that if you put a word in italics, it’s hardwired into the document as an italic word.

This means that no matter which version of the word processor opens the file, the word in italics will remain in italics.

In a digital ebook file this is different!

When a word document is converted to a format that can be read on an eReader, two very important things happen:

  • 1. The text is separated from the style.
  • 2. A ‘styling’ is stored in a separate file.

Let me explain.

Let’s say you write the following sentence in a Word document:

This sentence contains a word in italics.

If you then converted this to a format for an eReader you would get two things.

The first would be pure text that said:

This sentence contains a word in italics.

The second would be a separate file (called a CSS file), which tells the eReader that when rendering the word italics in this sentence, put it in an italic font.

When the eReader displayed the sentence it would initially render the text and then apply the CSS to make the word italics into italics.

The second thing to understand is that text is reflowable.

When using a word processor a page is a page.

A page contains a set number of words and when the page is full another is created.

This is NOT the case for eReaders.

To understand why you need to think of how ebooks are read.

The problem is that we don’t know what device a reader is going to use to read your book.

They could read it on a Kindle, but they could also read it on an iPhone, or any one of many different devices.

Most devices have very different screen sizes.

If we created ebooks with one set page size in mind, they would not fit correctly on any device but the one we had in mind when developing the ebook.

The solution is reflowable text.

This means that the eReader will fill the screen with your text and then just flow what remains into the next screen.

As far as an eReader is concerned there is no such thing as a page…

Just a screen to fill with text.

If the reader alters the screen size, no problem the text just flows to fit.


This means that as an ebook creator you have to stop thinking about pages and just think about text.

What Are The Major Ebook Formats?

I am hoping that the last section demonstrated that ebook formats are very different from word processor files (Word, Pages etc.).

This is a key point.

In short, a word processor file CAN’T work on an eReading device – it’s just not set up correctly (Word files are FIXED LAYOUT digital, while eReaders need REFLOWABLE text).

It’s like putting a vinyl LP in a DVD player and expecting it to work.

If you are going to make you book viewable on an eReader device you must convert it to a digital format.


There are a number of ebook formats out there.

However, I want to just give you enough information to get started.

Since the two most popular reading devices are the Kindle and the iPad, I want to focus on just two formats: Epub and Mobi.

All digital files (Epub and Mobi included) are, in fact, a collection of files.

For those with a technical knowledge, they are just files zipped together, but instead of calling them .zip we call them .epub or .mobi.

A digital file is more like a website than a Word file. In fact, a digital file has a close cousin to the website and shares many common structural features. As a side note, many people believe that, ultimately, ebooks will be read in web browser, but we digress.

If you were to open up an Epub or Mobi file you would find lots of smaller files.

I don’t want to go into the technical side of things too much, but I do want you to understand the basics.


All .epub and .mobi files contain:

  • A file that contains JUST the plain, un-formatted text.
  • A file that tells the eReader how to display elements of the text (this is the CSS, remember the italics?).
  • Lots of other files that contain all sorts of other information, such as images, ISBN, your name etc..

So why is this important?

It’s important because some people will tell you that converting a word processor file to a ebook format (epub/mobi) is simple.

IT IS NOT! If a digital file (Epub/Mobi) is not correctly prepared you will, potentially, face a huge problems when your book is read on a device you have not tested (think Kobo and Sony Reader).

In fact, even using the tools provided by Amazon to convert your files is not guaranteed to produce a ‘clean’ file.

What is Epub?

You should now understand that for a book to displayed correctly on multiple eReading devices you need a specific digital file.

The standard format, as recommended by the posh-sounding International Digital Publishing Forum is the Epub.

The Epub is an open format that means that is it not ‘owned’ by any one company or device.

Since Epub is the standard format, MOST eReaders will display an epub.

In fact, it is very easy to read an Epub with lots of free tools out there that will allow you to read an Epub on your computer.

It is even possible to read an Epub in a web browser, such as Firefox.

However, what really counts is eReaders and there are number of important devices that will reader Epub:

  • Apple iPad and iPhone.
  • Kobo eReader.
  • Barnes & Noble Nook.
  • Sony Reader.
  • Android phones.

You might notice that there is one, very important eReader missing from the list – the Kindle.

The Kindle WILL NOT read epub files.

That’s correct, the Kindle chooses NOT to allow Epub files to be read.

It’s unclear if this choice of Amazon not to display epubs files will alter in the future. Some believe that it will; others feel that while the Amazon store remains dominant, Amazon eReaders will continue to ignore Epub.

We are on the verge of the release of the next generation of Epub, called Epub3. Below is a video showing what will be possible with Epub3.

So What Is Mobi?

If Epub is the universal ebook format, what’s Mobi?

The answer is that Mobi is Amazon’s version of Epub.

In essence, Amazon have tweaked the Epub format to create Mobi files that can only be displayed as Mobi files.

That means that if you want to read a book on your Kindle you have no choice but to buy the book from the Amazon store. It also means that if you buy a book in Mobi format you can’t read it on a device that is not able to read Mobi files.

This is called DRM.

So what does that mean for you as a self-publishing writer?

It means that you have no option but produce TWO digital ebook formats of you book – Epub and Mobi.

The good news is that once you have an Epub file it’s a very simple process to convert it to Mobi.

God bless Amazon!

What should I do about converting?

I’m betting the reason you are reading this article is more about conversion than interest in technical formats.

By this point I am hoping that you now understand why you need to convert to a digital ebook format, and you have no option but to create an Epub AND Mobi file.

The question is how?

When it comes to converting from a word processor file (Word/Pages/OpenOffice) to Epub/Mobi you have three options:

1. The Meat Grinder

If you are going to upload to digital readers such as the Kindle and iPad, it is possible to use tools they provide to convert your book.

Let’s start with all key devices, other then the Kindle.

Apple only allows a select number of third-party companies to upload books to the iBook store.

This means that you, as a self-publishing writer, can’t just upload your book to Apple.

There are a number of companies out there that will help you upload to Apple, but I suggest you start by checking out Smashwords.

This company will allow automatically upload your book to a number of devices.

Though they don’t charge for this service, they do take a small cut of each book that is sold.

The big bonus with Smashwords is that they have developed a ‘meat grinder’.

This is an online system that allows you to enter your text and then convert to Epub.

At this point I would say that for some books this is the perfect option.

I will say that again – for some books this is the perfect option.

It may be that using Smashword’s free meat grinder is the perfect solution for you and your book.

However, for complex books, especially those with images, the meat grinder can produce variable results.

In this case, you may be looking at a different answer.

I have spoken to a number of writers that feel the meat grinder is simply not good enough to produce consistently ‘clean’ conversion.

Smashwords solves the Epub problem but what about the Kindle? Kindle is the gorilla in the marketplace and is where you will make the most sales.

This means that even if you do use Smashwords to upload to Apple iPad and a number of other eReaders, you still need to crack the Kindle nut.

The good news is that Kindle actually offer its own ‘meatgrinder’ solution in the form of a similar service at the Kindle Direct Publishing website.

Amazon provides free tools that you can use to convert your Word/Pages/OpenOffice document to a Mobi file.

Once again the quality of the conversion can vary.

If your book is a simple text document then KDP might be the perfect solution.

However, if your book is complex you may be forced to look elsewhere.

One final option is Pressbooks.

This is a free online tool that allows you to create ebooks from scratch.

It’s a WordPress-powered free online application that allows you to simply create ebooks at the push of a button.

I suggest you check them out if considering the ‘meatgrinder’ option.

2. DIY

So what if you don’t want to take the meat grinder approach? If this is the case then you are into Do It Yourself territory.

There are many software solutions to creating Epub files, some free and some paid.

However, my advice here is to be cautious: it’s a very steep learning curve.

It is NOT a simple case of downloading some free software and pressing a button.

You will need a deeper understanding of the Epub design, as well as a passing knowledge of HTML and CSS.

This said, if you are considering producing a lot of Ebooks, then DIY may be a very viable option.

3.Professional Help

The final option is to pay someone to convert your book for you.

Like anything else this is buyer beware.

As we have learned creating an ebook from scratch is not an easy process.

My advice is to look for a professional who has come recommended and is prepared to show you a sample of their work.

The cost varies greatly depending on size and complexity of the book, but a figure of $100 would be a good starting point for an average novel.

We actually offer this service to our writers. If you want us to convert your book then fire over an email and we can discuss your needs.


The final point worthy of mention is book covers.

You will need a cover for your book.

You will need this cover to be of the correct size and resolution.

Once again we are in a situation where you will need to weigh up the cost of paying a professional and the cost in your time in learning to design a cover.

Again the pricing can vary greatly but a figure of $200 would not be unusual.

If you have any further questions, feel free to email me at [email protected].

About the Author

By Gary Smailes - Co-founder at BubbleCow, helping writers to write, get published and sell more books. Google+ Twitter

  • http://cavalrytales.wordpress.com/ unclearthur

    Just wondered if you’d tried Calibre and what you thought?

  • Laurapauling

    This is a terrific breakdown. I needed it 2 weeks ago though! After muddling through formatting I now understood everything you talked about. :)

    I checked out the Unruly Guides and though kind of straightforward, be prepared not to have full control over style elements - unless you are familiar with CSS and can tweak it yourself. 

  • Don’t forget scrivener’s epub and .mobi feature. Great blog..thanks for the info.

  • http://bubblecow.net BubbleCow [Gary Smailes]

    To be honest I have not had any experience with output. Would love to hear from anyone that has. How clean was the output? Did it look good on Amazon?

  • http://bubblecow.net BubbleCow [Gary Smailes]

    Laura - this is a great point. I have been using CSS for years. I am even comfortable with HTML5 and Javascript… However, I find playing with the insides of any ebook very off putting. I think the big issue is the problems that you face across eReaders. I always worry that though a book looks good on the Kindle, it could be a disaster on the Nook.

  • http://bubblecow.net BubbleCow [Gary Smailes]

    I have just had a long conversation with our ebook conversion guy. He basically said that Calibre produces a ‘messy’ output. He thinks it is great for converting books for your own consumption, but he felt that using Calibre for a book you intend to sell for cash is asking for trouble. 

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  • http://profiles.google.com/odyssey9794 Peter Hart

    What you said is DRM, is not. What your ebook conversion guy “basically said” about Calibre was incomplete and inaccurate. The fact that you speak about all of the problems that one might face when converting one’s own ebooks, and then reveal that you offer that service for money, rightly makes your whole post suspect.

  • http://bubblecow.net BubbleCow [Gary Smailes]

    Hi Peter,

    I am sorry that you feel our expert’s advice is someway diminished by the fact we offer ebook conversion as a service.

    Our aim is to provide ‘high quality’ advice to writers looking to self-publish. We are in a unqiue position in that we see two sides of the industry and are, therefore, able to provide insights that others might not see.

    However, I would love to hear more about your experiences with Calibre. The only feedback I have heard in regards to Calibre converted documents being used on multiple ereaders has not been great.


  • http://bubblecow.net BubbleCow [Gary Smailes]

    Wiki defines DRM as ‘Digital rights management (DRM) is a class of access control technologies that are used by hardware manufacturers, publishers, copyright holders and individuals with the intent to limit the use of digital content and devices after sale.’

    Surely Kindle producing its own version of epub (mobi) and then only allowing that format to be displayed is DRM?

  • Janet Oakley

    What a great article. Truly. Made a lot of things clear to me. Thanks.

  • http://www.ezekelalan.com Ezekel Alan

    Thanks for this blog Bubblecow, it was a very useful one. Wished I had seen this a few months ago when I started my self-pub journey and the deep dive into e-book formats. I have been following your blog since a friend brought it to my attention. Very helpful guides. One love.

  • Jacques

    I use Atlantis Word Processor to convert MS Word documents to EPUB:

    There are a bunch of videos on their site about creating eBooks:

    Then use kindlegen to convert EPUB to MOBI.

    Have anyone tried Atlantis Word Processor?

    And what about Sigil:

  • Gary Smailes

    Brilliant - thanks!

  • My Name

    I haven’t yet published on the Amazon Kindle, but after reading a lot of advice and trying things (all free - that is my budget!), this is how I do it so far:

    Open Office Writer - create document
    Save as HTML
    Open the HTML in Callibre, save it as an EPub
    Open the EPub in Sigil
    Click the green check mark in Sigil to find and correct all the errors.
    Save it as a mobi.

    I’m hoping this will make me end up with an error-free mobi to upload to Kindle. Btw in Callibre you can save as mobi too, but it’s easier to see and correct the errors if you use Sigil.

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  • kitten dark

    mobi is not a version of epub. mobi format was created by a french company. Amazon bought the format, and they did developed it further, into a new format, azw.

    DRM has nothing to do with format, except wheter it is suported or not (you can apply or not DRM to the ebook format). For someone who is offering this services as a professional, you should have these things straighten up.

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  • Gary Smailes


    Thanks for the comment.

    You are indeed correct about the origin of mobi. However, in a ‘quick guide’ designed to make the water less muddy I felt this was not relevant information. The same applies to the subtleties of the structural relationships between epub and mobi.

    As for DRM, my understanding is that it applies to the ebook being locked to one company or device. It is the mobi format that makes this possible. If Amazon allowed you to buy ebooks in epub format the DRM would dissolve (as would the marketshare of the Kindle). http://en.wikipedia.org/wiki/MOBI


  • Matthew Belanger

    exactly what I found out when I published my wife’s first book “Bumbaarai” on Kindle. I ended up doing it myself and had to revise a few times to get it right. Thanks for writing up this forum :-)

  • IS

    after we upload an e-book ourselves, is it possible to review it before it is published for sale? This would help in catching the errors?

  • racheledits

    Excellent explanation of some basic points, relevant even two years later. Aside from a few grammatical errors I noticed (sorry, I’m an editor!), I appreciated the conversational style of this article, which helped in understanding the relationship (or non, as the case may be!) of formats to devices. Thank you! Cheers from Canada!

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