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How It Works • File Formats

EPUB

EPUB is an open standard file format for digital publications, especially e-books.

Updated September 11, 20261 min readCited sources

EPUB is an open standard file format for digital publications, especially e-books. Its name is short for electronic publication, and files typically use the .epub extension.

What it is

EPUB is a vendor-independent open standard for digital books and other publications. An EPUB file is a ZIP-based archive that contains web-style content such as XHTML/HTML, CSS, images, fonts, and metadata. The format is designed to be reflowable, allowing text to adapt to different screen sizes and orientations.

Why it matters

EPUB is widely supported by e-readers, mobile apps, smartphones, tablets, and computers, making it a versatile choice for digital reading. Its reflowable layout is especially useful for varied screen sizes, and it is commonly used by library systems and publishers in Canada for accessible digital materials.

Key details

EPUB became an official IDPF standard in September 2007. EPUB 3 later extended the format for richer web-based features and is recognized as an ISO standard. The format is maintained through the W3C EPUB 3 Community Group.

In short

  • EPUB is an open, ZIP-based e-book format with reflowable content.
  • It adapts text to different screen sizes and devices.
  • Standardized in 2007 by IDPF, now part of W3C and ISO.
  • Widely used in Canadian libraries and publishing.
Canadian angle

EPUB is relevant to Canadian readers because it is widely supported by library systems, publishers, and e-book devices used in Canada, and it is commonly used for accessible digital reading materials.

Quick questions

What does EPUB stand for?
EPUB stands for electronic publication.
What file extension does EPUB use?
EPUB files use the .epub extension.
Is EPUB only for books?
No. It is primarily used for e-books, but it is also a general digital publication format for other structured content.

Sources

  1. Wikipediahttps://en.wikipedia.org/wiki/EPUB
    Supports: Definition, file extension, 2007 standardization, ZIP-based structure, wide support
  2. Adobehttps://www.adobe.com/acrobat/resources/document-files/epub.html
    Supports: Definition, reflowable design, typical use, device compatibility
  3. Publications Office of the European Unionhttps://op.europa.eu/en/web/accessibility/transcript-introduction-to-accessible-epubs
    Supports: EPUB 3 description, ZIP-based archive, resources included, ISO standard note
  4. World Wide Web Consortiumhttps://www.w3.org/TR/epub-overview-34/
    Supports: EPUB 3 overview and packaging of web content