FB2 File Format (.fb2)

An FB2 file is a single XML document that holds an entire book's text, metadata and base64-encoded cover images, in the FictionBook format that originated in the Russian-language ebook scene.

.fb2Documents

FB2 at a glance#

Full name	FictionBook 2
File extension	.fb2
Category	Documents
Developer	Dmitry Gribov
First released	2004
Compression	Uncompressed
Specification	FictionBook 2 XML Schema
FileFlip support	FileFlip reads and writes this format

What a .fb2 file can hold#

These are the things a FB2 file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.

Embedded metadata	Yes
Multiple images or pages	Yes
Selectable text	Yes
Chapters	Yes
Human readable	Yes

Strengths and limitations of FB2#

What FB2 does well

Describes a book's structure with tags for epigraphs, verse and quotations rather than just formatting
Keeps the whole book, its metadata and its cover image in one plain XML file with no separate container
Widely supported by readers popular in Russian-language ebook collections, like FBReader and ICE Book Reader

Where FB2 falls short

Kindle, Nook and other major commercial readers have no native FB2 support
Base64-encoding every image inside the XML inflates file size compared to storing images as binary
Being purely structural, it has no equivalent to EPUB's fixed layout for anything besides running text

Keep a book as FB2 when it is sourced from a Russian-language ebook library and the reader is FB2-native, such as FBReader or a PocketBook device.

Convert FB2 to EPUB to read the book on a device or app outside the small set of readers that understand FictionBook directly.

How to open a .fb2 file#

A .fb2 file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts FB2 into a format your machine already opens, and it does it in the browser tab rather than on a server.

Platform	Programs that open it
Windows	Calibre, SumatraPDF, ICE Book Reader
macOS	Calibre
Linux	Calibre, Okular, FBReader
Android	FBReader, Moon+ Reader
Web	FileFlip

FB2 questions people ask#

What is an FB2 file?

An FB2 file is an ebook in the FictionBook format, a single XML document that holds the full text, metadata and any cover image in one file rather than the zipped archive EPUB uses. It was created in 2004 and is most common in Russian-language ebook collections.

Can I open an FB2 file on a Kindle?

Not directly. Kindle devices do not read FB2, so the file needs converting to EPUB or MOBI first, either through Amazon's Send to Kindle pipeline or a separate converter.

What reader apps open FB2 files?

FBReader, Calibre, Okular and SumatraPDF all read FB2 files natively, and it is also the default format on many e-readers sold in Russian-language markets. Mainstream apps like Apple Books and the Kindle app do not.

Converting FB2 files#

Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.