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Free Online EPUB to FB2 Converter

Convert EPUB to FB2 online for free.

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EPUB vs FB2: Side-by-side

Technical comparison of the two formats — useful for deciding which to use, or for confirming what changes during conversion.

Property EPUB FB2
Full name Electronic Publication FictionBook 2
Year introduced 2007 2004
Developer / standard body W3C (formerly IDPF) FictionBook (open)
MIME type application/epub+zip application/x-fictionbook+xml
File extension .epub .fb2
Compression ZIP-compressed XHTML + CSS XML (typically uncompressed)
Color / data depth N/A N/A
Max dimensions / size Software-limited Software-limited
Transparency No No
Animation No No
Standard / specification W3C EPUB 3.3 / ISO/IEC 23736 FictionBook (open)
Best for Apple Books, Kobo, Nook, Google Play Books — reflowable text Russian-speaking ebook community, lightweight ebook archiving

About the EPUB Format

EPUB (Electronic Publication) is the most widely adopted open ebook standard, maintained by the W3C (formerly IDPF) and published as ISO/IEC 23736. First released in 2007 as the successor to the Open eBook format, EPUB uses XHTML for content, CSS for styling, and ZIP compression for packaging. Its defining feature is reflowable text — content automatically adapts to fit any screen size, allowing readers to adjust font size, margins, and line spacing on phones, tablets, and dedicated eReaders.

EPUB is natively supported by Apple Books, Kobo, Nook, Google Play Books, and nearly every eReader and reading app outside the Kindle ecosystem. EPUB 3, the current version, adds support for embedded fonts, SVG graphics, MathML equations, JavaScript interactivity, audio/video embedding, and comprehensive accessibility features including text-to-speech and screen reader support. While Kindle devices do not read EPUB natively, the format can be converted to MOBI or AZW3 for Kindle compatibility.

EPUB to FB2 FAQ

Quick answers about compatibility, quality, metadata handling, and the most common reasons to convert EPUB files to FB2.

Can I convert EPUB books to FB2 for my Kindle or Kobo?

Yes. Upload your EPUB ebook and iFormat converts it to FB2 with chapter structure, cover art, and formatting preserved. Load the FB2 onto your Kindle, Kobo, Nook, or any eReader that supports the format.

How to convert EPUB to FB2 without losing the table of contents

Chapter navigation, the cover image, and text formatting all carry over during conversion. The FB2 has proper chapter links so you can jump between sections on your eReader just like the original EPUB.

Can I convert multiple EPUB ebooks to FB2 at once?

Yes — upload a batch of EPUB files and iFormat converts them all to FB2. Each book downloads separately or as a ZIP, so you can convert an entire library in one session.

Does the text still reflow after converting to FB2?

Yes — FB2 keeps text reflowable, so it adapts to any screen size and font setting on your eReader rather than being locked to a fixed page like a PDF.

Which reader is FB2 for?

FB2 is the FictionBook ebook format best for FictionBook readers. Convert your EPUB to FB2 when your eReader or app opens FB2 more reliably, so the whole library works on one device.

Is there a file size limit for EPUB to FB2 conversion?

The free plan supports files up to 50 MB, which covers the large majority of EPUB files. For longer or higher-resolution files, Starter raises the limit to 100 MB, Plus to 1 GB, and Pro to 5 GB.
Need the reverse conversion?
Convert FB2 back to EPUB with our companion tool.
FB2 to EPUB converter
Reviewed by Editorial team Updated