Novus Convert
Convert files
Ebook format

EPUB converter

EPUB is the open, vendor-neutral standard for reflowable ebooks, and the .epub extension marks a book whose text rewraps to fit any screen size or font preference. Under the hood an .epub file is an ordinary ZIP archive holding XHTML chapters, stylesheets, images, and a manifest that tells the reading app what to display in what order.

Private for supported formats — processed in your browser

Convert supported files

Runs on your device

Drop EPUB files here

Batch files can each use a different output. Nothing uploads for local conversions.

Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.

Where EPUB comes from

The International Digital Publishing Forum published EPUB in 2007 as the successor to the older Open eBook format. EPUB 3 followed in 2011, rebasing the standard on HTML5 and adding audio, video, MathML, and fixed-layout support. Stewardship passed to the W3C when the IDPF merged into it in 2017.

How EPUB works

  • A ZIP container whose first entry must be an uncompressed file named mimetype identifying the archive as an EPUB.
  • Content is XHTML plus CSS, organized by an OPF package document whose spine defines the linear reading order.
  • EPUB 3 permits embedded fonts, SVG, MathML, scripting, and synchronized audio narration via Media Overlays.
  • Navigation comes from an XHTML nav document in EPUB 3 or an NCX table of contents in EPUB 2.
  • An optional fixed-layout mode pins each page to exact dimensions for comics and picture books.

When to use EPUB

  • Distributing self-published novels through stores like Kobo, Apple Books, and Google Play
  • Reading on adjustable-type devices where users control font size and margins
  • Library lending through OverDrive and Libby, which deliver EPUB under the hood
  • Accessible publishing, since screen readers navigate its HTML structure well
  • Packaging a manuscript into a single portable file for beta readers

Strengths and limitations

Strengths

  • Reflows to fit any screen, font size, or orientation
  • Open, royalty-free specification with no vendor lock-in
  • Supported by nearly every reading app and e-reader outside Amazon hardware
  • HTML and CSS internals make it easy to build, inspect, and repair

Limitations

  • Kindle devices cannot open a sideloaded .epub directly; Amazon converts it during Send-to-Kindle delivery
  • Rendering differs between reading apps, so precise layouts are hard to guarantee
  • Store-purchased files often carry DRM that blocks format conversion

Compatibility

Virtually every reading system outside Amazon opens EPUB natively, including Kobo, Apple Books, Google Play Books, and open-source apps such as Calibre and Thorium. Amazon has accepted EPUB uploads through Send-to-Kindle since 2022, though the file is converted to a Kindle-internal format on delivery rather than rendered as-is.

The OPF package embeds Dublin Core metadata — title, creator, language, identifier, publisher, and date — alongside a declared cover image; tools such as Calibre extend it with series and rating fields.

Convert EPUB to another format

Convert other formats to EPUB