Document format
What is a .epub file?
EPUB is the open standard for e-books. Its text reflows to fit the screen, so it reads comfortably on phones, tablets and e-readers.
An EPUB is a ZIP of web files: HTML, CSS and images. Almost every e-reader opens it, and Kindle accepts it through Send to Kindle.
fileclay opens and writes EPUB
EPUB vs PDF vs FB2
| EPUB | FB2 | ||
|---|---|---|---|
| Layout | Adapts to the screen | Fixed | Adapts to the screen |
| Reading on a phone | Comfortable | Zoom needed | Comfortable |
| Images and styles | Yes | Yes | Basic |
| Best for | E-books | Final documents, forms | Fiction in Russian-language libraries |
When to use EPUB
Good for
- Novels and long texts
- Reading on e-readers and phones
- Publishing a book
Not a good fit
- Documents that must keep an exact layout
- Forms and contracts
- Heavy design, such as magazines
How to open .epub files
| Platform | App | Notes |
|---|---|---|
| iPhone, iPad, macOS | Books | Built in |
| Windows | Calibre, Thorium Reader | Free |
| Android | Google Play Books | Upload the file |
| E-readers | Kobo, Kindle | Kindle through Send to Kindle |
Convert EPUB files
How to identify a .epub file
An EPUB is a ZIP, so it starts with “PK”. Its first file is called mimetype and contains “application/epub+zip”.
50P
4BK
03
04
It’s read here, in your browser. Only the first bytes.
Your file
What comes after
mimetypeSays that it is an EPUB
META-INF/Where the book starts
OEBPS/Chapters, styles and images
Questions about EPUB
Can Kindle read EPUB?
Yes, through Send to Kindle, which converts the file.
Is EPUB better than PDF for reading?
On small screens, yes: the text adapts. PDF keeps the exact page.
Does converting PDF to EPUB keep the layout?
No. The text is reflowed, so complex pages change.
Can I edit an EPUB?
Yes, with Calibre or Sigil.