By Dave Chesson
Different bookstores require different file types in order to submit your book to them. Furthermore, many allow for multiple different file types for either ebook or book submissions.
So, when there are different options, this leaves many authors wondering which is the best file type they should format their book for and submit.
Luckily, this article has been created to help answer exactly that.
But before we get into that, we’ll first need to discuss what the file types are and some of the key terminology you’ll need to understand so as to be able to make better formatting decisions in the future.
What Are the File Types?
For print and ebook, there are five book formats that have established themselves over the years:
- Standard EPUB Format
- Fixed Layout EPUB (for complex and coloring books)
- Fixed Layout for Kindle
(Kindle Format 8, or KF8)
- PDF for print books
* Effective June 28, 2021, Amazon is no longer supporting the MOBI file format. They are also not accepting PRC or AZK as well. You can instead use EPUB or KF8.
The EPUB format is used by most self-publishers while the Fixed Layout formats are tailored to graphically heavy ebooks. Let’s look at all formats in more detail.
There are still other formats out there like HTML, Rich Text Format (RTF), Plain Text (TXT), and more. But many of these are very hard to work with and usually have extra stipulations in order to get to work.
Samantha Howard of Nerdy Book Girl says that “Even though using HTML, RTF and even TXT can provide more options, they are ridiculously hard to manage and format correctly. Authors are more likely to have their files rejected by markets trying to use them.”
Therefore, they are not recommended.
So, now that we’ve covered the most known and used, let’s go ahead and dissect each a bit more, and understand some of the terminology.
Reflowable vs. Fixed-Layout E-Books
Standard EPUB formatting allows the text of your book to “reflow” to the shape of the device. In consequence, you can only use the most basic book design—the fonts are pre-determined by the reader, images can be inserted inline with the text.
This format accounts for the possibility that the reader might read the book on all the different devices: a dedicated eReader, a big computer screen, a tablet, or a mobile phone. It also precludes the possibility that a reader might want to change the font size.
But not all books work in that way, for example cookbooks, comic books, illustrated textbooks, pictured kids books or graphic novels.
For those, the fixed layout ebook is the better choice. It does not reflow but can look beautiful on tablet computers and devices with colored screens.
There are two main standards:
- Fixed‐Layout EPUB for all devices
- The Kindle Fire 8 (KF8) format for Amazon devices.
Be aware that this format has its weaknesses. Hardware devices come in many shapes and sizes and offer different features—varying aspect ratios, capabilities for zooming, panning, page viewing, multimedia—which makes it impossible to design one fixed‐layout ebook that works on every device.
But if you know what devices your customers are using and can commit to one, it can be worth it.
Also, you will need to either work with a designer or have excellent skills in book design concepts to make your fixed‐layout ebook a success.
When Amazon first came out with ebook publications and Amazon Kindle Publishing, Mobi was THE file. It was their own creation and they were pretty much the only store that required it. Therefore, for most authors, it became a staple for ebook formats.
However, as was discussed about, Amazon is now shifting away from Mobi and will be accepting EPUB as the main reflowable ebook format.
So, no longer should authors push to make Mobi files for their ebooks.
Standard EPUB Format
In 2007, the International Digital Publishing Forum released the first EPUB standard. Everyone uses this format for ebooks, including Amazon. Other major stores like Apple, Kobo, and B&N Nook sell in this format, and EPUB can be read on most eReader devices and apps.
If you are not using a distributor like Draft2Digital or Publish Drive, there are some specifications you should be aware of. For example, Barnes & Noble requires a slightly different EPUB file with specific instructions. Apple and Google Play opt for a validation check you will need to pass to upload and sell your ebook on their store.
Because EPUB is so widely accepted and easy to create using different book formatting software or freelance formatters, this is the preferred formatting file type.
PDF Format for Print
Before you format and export your book for print, decide on your trim size, which is the book’s physical size. For print, there are a variety of sizes you can use, but mostly two standards for your usual fiction or non-fiction book:
- US Trade 6″ x 9″ is the most common size for trade paperbacks and hardcovers, used primarily for fiction.
- Digest 5.5″ x 8.5″ is a smaller trade size, one of the most commonly used sizes for fiction and nonfiction works.
There is also the Pocket Book 4.25″ x 6.87”, the Comic Book 6.625″ x 10.25“, Landscape and Square book sizes, and countless more you can use for the specific needs of your book.
For print, book margins are also crucial. A print book is laid-out as a “mirror image” format. Pages on the left and right are different: left-hand pages mostly have a narrow left-hand margin and a wide right-hand margin, right-hand pages the opposite.
With standard EPUB and MOBI formats, you have nearly no control over the design, so there are not as many things to consider and mistakes to make as in print formatting. If you want your book to be available in print, you should consider to either work with a professional designer or a software that takes care of these technicalities for you.
Regardless of what trim size you chose for your book, the format you export it in for print should always be PDF.
Formatting your book can be a formidable task. Just look at this 7000 word guide on all the different steps and actions one needs to take.
However, that being said, if you don’t know which file types you want to format with, it will only complicate things even more so. Plus, it will be hard to figure out how you want to proceed in your formatting.
Therefore, with this article, I hope you have a clear understanding of the two types that should be followed and why.
With EPUB, you can now enter every market, including Amazon. With PDF, you stand the best chance of not being rejected.
Dave Chesson is the creator of Kindlepreneur.com, a website devoted to teaching advanced book Marketing which even Amazon KDP acknowledged as one of the best by telling users to “Gain insight from Kindlepreneur on how you can optimize marketing for your books.” Having worked with such authors as Orson Scott Card, Ted Dekker and more, his tactics help both Fiction and Nonfiction authors of all levels get their books discovered by the right readers. He’s also the founder of Publisher Rocket, and Atticus.