What is an EPUB file?
EPUB is the open e-book standard maintained by the W3C. An EPUB file is a ZIP package of XHTML chapters, CSS style sheets, images and a manifest that lists the reading order. Because the content is essentially a small website, text reflows to fit any screen size and font setting, which is what makes e-books comfortable on phones and e-readers.
EPUB 3 added audio, video, MathML, scripting and a fixed-layout option for comics and picture books. Nearly every reading app supports EPUB, with Amazon's Kindle the long-standing exception; Kindle devices accept EPUB via Send to Kindle, which converts it on the way.
When EPUB is the right choice
Strengths
- Reflowable text adapts to screen size, font and night mode
- Open standard read by Apple Books, Kobo, Google Play Books and most apps
- Small files: text and styles compress well
Limitations
- Layout-heavy content such as textbooks and manuals loses its page design
- Kindle devices need conversion or Send to Kindle
- Purchased books are often locked with DRM and cannot be converted
How to open an EPUB file
Apple Books, Google Play Books, Kobo, Calibre, Thorium Reader and browser extensions open EPUB; Windows users can use Calibre or the Edge browser with an extension. For a printable copy with fixed pages, convert with the e-book converter to PDF.
How to convert an EPUB file
The e-book converter turns EPUB into PDF for printing, into MOBI or AZW3 for older Kindles, or into FB2 and other reader formats, and it converts those formats back into EPUB. DRM-protected books cannot be converted; only files you own without protection work.