What Is an Ebook?
An ebook is a book in digital form that you read on a phone, tablet, computer or e-reader. Learn the definition, formats like EPUB and PDF, types of ebooks and how they differ from print.
By Philip GhezelbashAn ebook (short for electronic book) is a book in digital form that you read on a screen, such as a phone, tablet, computer or e-reader. Merriam-Webster defines it as “a book composed in or converted to digital format for display on a computer screen or handheld device.” An ebook can be a novel, a how-to guide, a workbook, a cookbook, or a short free guide that a business gives away to grow its email list.
This guide explains what an ebook is, how ebooks began, the file formats you will meet, the main types, and how an ebook differs from a print book. We checked the facts and figures in October 2026.
What counts as an ebook
An ebook is a book whose content is a digital file. Like a print book, it usually has a cover, a table of contents and chapters. Unlike print, it can include links, search and adjustable text size. You will see the word spelled ebook, e-book and eBook. They all mean the same thing, and Merriam-Webster lists “ebook” as the main spelling.
Not every digital document is called an ebook. People usually use the word for something with book-like structure and enough content to be read as a whole: a guide, a book, a report or a course workbook, rather than a one-page flyer.
A short history of ebooks
- 1971: Michael Hart began Project Gutenberg at the University of Illinois. Its first text was the Declaration of Independence, and the files were plain text.
- 1998: The first handheld e-readers went on sale, including NuvoMedia’s Rocket eBook and the SoftBook reader, according to Publishers Weekly.
- 2007: Amazon launched the Kindle on November 19, 2007, at $399. The same year, EPUB became an official standard.
- 2010: Apple launched iBooks, now called Apple Books.
- 2026: EPUB 3.3 became a W3C Recommendation on January 13, 2026.
Sources: Project Gutenberg, Publishers Weekly, W3C and Wikipedia for the Kindle and EPUB dates.
Ebook formats
The format is the type of file. The two you will see most are EPUB and PDF.
| Format | What it is | What it is used for |
|---|---|---|
| EPUB | An open standard that packages a book’s text, styles and images in one file. Text reflows to fit the screen by default. | The main format for ebook stores and e-readers. Apple Books, Kobo and Google Play Books use it. |
| A fixed-page document that looks the same everywhere. | Guides, workbooks and direct downloads where the layout must not change. Google Play Books accepts PDF. | |
| Kindle formats | Amazon’s own formats, called AZW3 and KFX. You do not make these yourself. | Books sold on Amazon. KDP converts the file you upload. |
| Word, HTML and text files | Editing formats. | KDP accepts them as uploads and converts them, but stores do not deliver them to readers. |
What to upload to each store:
- Amazon KDP accepts EPUB (2.0 or 3.0), DOCX and KPF for reflowable books. KDP no longer accepts MOBI files since March 18, 2025.
- Apple Books accepts EPUB.
- Google Play Books accepts EPUB and PDF.
Our guide to PDF vs EPUB explains which to choose, and the free EPUB checker tests an EPUB before you upload it.
Reflowable and fixed layout ebooks
A reflowable ebook adapts to the screen. If a reader makes the text bigger or changes the font, the pages re-flow. This is the default for most ebooks, and it suits books that are mostly text. A fixed layout ebook keeps every page exactly as designed, like a PDF, which suits books where the layout matters.
Apple’s guidance is to use reflowable EPUB for novels and books without many images, and fixed layout for children’s books, cookbooks and books with lots of illustrations or graphics. KDP says ebooks are reflowable by default.
Types of ebooks
| Type | What it is | Usual layout |
|---|---|---|
| Nonfiction books | How-to, business, self-help, health, history, memoir | Reflowable |
| Fiction | Novels, novellas and short stories | Reflowable |
| Guides and how-tos | Short practical books on one topic | Reflowable or PDF |
| Workbooks and templates | Guides with exercises or fill-in pages | Often PDF |
| Cookbooks | Recipes with photos | Often fixed layout |
| Children’s picture books | Illustrated books | Fixed layout |
| Lead magnets and white papers | Free or gated resources that build trust or collect emails | Usually PDF |
| Textbooks and course materials | Learning content | Varies |
HubSpot defines a lead magnet as “a marketing tool that generates leads by offering a long-form resource in exchange for a prospect’s contact information.” A white paper, in Merriam-Webster’s business sense, is “a detailed or authoritative report.” If you want to see what makes a good one, read our guide to creating a lead magnet ebook, and our list of ebook ideas if you are choosing a topic.
How people read ebooks
People read ebooks on dedicated e-readers and in apps:
- Kindle devices and the Kindle app (iPhone, Android, iPad, Fire tablets, PC and Mac).
- Apple Books on iPhone, iPad, Mac and Apple Watch.
- Google Play Books on Android, the web, iPhone and iPad.
- Kobo e-readers and the Kobo Books app.
You do not need a special device. A phone and a free app are enough.
Ebook vs print book: what matters to authors
| Ebook | Print book | |
|---|---|---|
| Cost to produce | No printing cost. KDP’s 70 percent royalty option subtracts a delivery fee based on file size. | KDP charges a printing cost for each copy: a fixed fee plus a cost per page. On the US store, for black ink on 110 to 828 pages it is $1.00 plus $0.012 per page. |
| ISBN | Not needed on KDP. | Required on KDP for paperbacks and hardcovers. |
| Royalties on KDP | 35 percent or 70 percent, depending on territory and price | A percentage of the list price minus the printing cost |
| Updates | You can update the file after publishing | You upload new files and the next printed copies change |
| Reader experience | Searchable, adjustable text, instant delivery | Physical object, no device needed |
On KDP’s US store, the 70 percent option applies to prices from $2.99 to $12.99, effective July 7, 2026, after the top of the band was $9.99. Our free KDP royalty calculator shows what each sale pays.
How many people read ebooks
Print still leads, and ebooks are a steady share. The Pew Research Center surveyed US adults in October 2025 and reported in April 2026 that in the past 12 months 64 percent had read a print book, 31 percent had read an ebook and 26 percent had listened to an audiobook. Seventy-five percent had read at least part of a book in some format.
On the sales side, the Association of American Publishers reported that US ebook revenue was $2.2 billion in 2025, up 3.2 percent. For comparison, hardcover was $8.2 billion, paperback $8.0 billion and digital audio $2.5 billion, out of $33.4 billion in total. Sources: Pew Research Center and the AAP StatShot annual report.
What is DRM?
DRM stands for digital rights management. Britannica describes it as the protection of copyrighted works by various means to control or prevent digital copies from being shared. On KDP you choose whether to apply it. KDP says DRM limits readers to Kindle apps and devices. For books confirmed as DRM-free, verified purchasers can download EPUB and PDF copies, which KDP says started on January 20, 2026.
How to make an ebook
Making an ebook has four steps. Each has a guide on this site.
- Choose a topic and a reader. Our ebook ideas post can help, and our guide to how long an ebook should be shows how long it needs to be.
- Plan and write it. Start with a free outline. Our full guide is how to write an ebook.
- Design the cover and format the file. See how to design an ebook cover, and check the file with the EPUB checker.
- Publish it. Our guide to self-publishing an ebook covers every step. Start with how to publish an ebook on Amazon KDP, and see where to sell ebooks for other stores.
FAQ
What does ebook stand for?
Ebook stands for electronic book. It is also written e-book or eBook.
Is a PDF an ebook?
In a broad sense, yes. A PDF is a digital document you read on a screen, and some stores accept it. But a PDF keeps fixed pages, while an EPUB reflows to fit the screen. Our guide to PDF vs EPUB covers when to use each.
Is an ebook the same as a Kindle book?
Not quite. A Kindle book is an ebook sold through Amazon in a Kindle format. Ebooks are also sold on Apple Books, Kobo and Google Play Books, and by authors directly.
Do ebooks need an ISBN?
Not on Amazon KDP, where KDP says you do not need an ISBN for ebooks. An ISBN is optional on Apple Books and Kobo, and Google Play Books does not require one. Read do you need an ISBN for an ebook for the details.
Can I read an ebook without a Kindle?
Yes. You can read ebooks on a phone, tablet or computer with a free app such as Kindle, Apple Books, Google Play Books or Kobo.
How long is an ebook?
There is no fixed length. A short guide can be a few thousand words and a full book can be tens of thousands. See how long an ebook should be.
Where Koobe fits
If you want to make one, Koobe turns an idea into a complete nonfiction ebook: an outline you can edit, chapters, four cover options, and files ready for stores. Your first book is free to create and preview.
Describe your book in a sentence. Koobe plans the chapters, writes them, designs the cover and exports a PDF and EPUB. Your first book is free.
“Files were ready for KDP, which is what I actually needed. First book I’ve finished.”