Reference

FB2

FB2 (FictionBook) is an XML-based ebook format that stores a whole book — text, structure, and metadata — in a single file. It is popular in Eastern European ebook communities and reflows text to fit any screen, similar in purpose to EPUB.

Files & formatsGeneral

FB2

Also known as: .fb2 file, FictionBook, FictionBook 2

XML-based ebook in a single file
Reflowable text, like EPUB
Popular in Eastern European ebook communities

What an FB2 file holds

An .fb2 file is a single XML document describing the book: chapters, paragraphs, formatting, author and title metadata, and often a cover and images encoded inside the file. Because it is XML, it is plain text and reflows to fit any reader.

FB2 emphasizes clean semantic structure, which makes it easy to convert into other formats. It is widely used in Russian and Eastern European ebook collections and supported by many e-readers and conversion tools.

FB2 vs EPUB and storage

Like EPUB, FB2 is a reflowable text format, so it suits novels far better than a fixed-layout PDF. The main difference is that EPUB is a ZIP of web files while FB2 is a single XML document; EPUB has broader device support.

Ebooks are small — usually well under a megabyte for text, more if images are embedded — so a large library barely affects storage. Readers and apps like Calibre convert freely between FB2, EPUB, and MOBI.

Related terms

Keep reading the reference.

Files & formatsEPUBEPUB is the open standard format for ebooks. It is a ZIP package of HTML, CSS, and images, and its text reflows to fit any screen size — unlike a PDF, which keeps a fixed page layout. Most e-readers except Amazon Kindle support it natively.General Files & formatsMOBI (Kindle ebook)MOBI is an ebook format originally from Mobipocket that Amazon adopted for early Kindle devices. It holds reflowable book text with chapters and basic formatting, but Amazon has retired it in favor of newer Kindle formats and no longer accepts MOBI uploads.General Files & formatsXMLXML (Extensible Markup Language) is a text-based format that stores structured data inside nested, custom-named tags, such as `<title>…</title>`. It is self-describing and widely used for documents, configuration, RSS feeds, and data exchange between systems.General Files & formatsPDFPDF (Portable Document Format) is a fixed-layout document format that looks the same on any device. Most PDFs are small, but scanned documents and image-heavy files can grow large, and they accumulate quietly in Downloads and the Files app.General