Free Online FB2 to MOBI Converter
Convert FB2 to MOBI online for free.
Drop FB2 files here
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Up to 50 MB per file. Sign up free to convert files up to 100 MB.
Selected files
| File name | Size | Convert to |
|---|
Preparing files
Checking files and selected output formats.
When MOBI is the right output
MOBI is Amazon's older Kindle format, now largely superseded by AZW3 and KFX. Convert to MOBI when you need side-load compatibility with older Kindle devices (pre-2015 Paperwhite and earlier) or when a self-publishing service specifies MOBI. For modern Kindles, upload EPUB directly to Amazon KDP and let Amazon transcode.
FB2 vs MOBI: Side-by-side
Technical comparison of the two formats, useful for deciding which to use, or for confirming what changes during conversion.
| Property | FB2 | MOBI |
|---|---|---|
| Full name | FictionBook 2 | Mobipocket eBook |
| Year introduced | 2004 | 2000 |
| Developer / standard body | FictionBook (open) | Mobipocket / Amazon |
| MIME type | application/x-fictionbook+xml | application/x-mobipocket-ebook |
| File extension | .fb2 | .mobi |
| Compression | XML (typically uncompressed) | PalmDOC compression |
| Color / data depth | N/A | N/A |
| Max dimensions / size | Software-limited | Software-limited |
| Transparency | No | No |
| Animation | No | No |
| Standard / specification | FictionBook (open) | Mobipocket |
| Best for | Russian-speaking ebook community, lightweight ebook archiving | Older Kindle devices (replaced by AZW3 then KFX) |
Frequently asked questions
Can I convert FB2 books to MOBI for my Kindle or Kobo?
Yes. Upload your FB2 ebook and it converts to MOBI with chapter structure, cover art, and formatting preserved. Load the MOBI onto your Kindle, Kobo, Nook, or any eReader that supports the format.
How to convert FB2 to MOBI without losing the table of contents
Chapter navigation, the cover image, and text formatting all carry over during conversion. The MOBI has proper chapter links so you can jump between sections on your eReader just like the original FB2.
Can I convert multiple FB2 ebooks to MOBI at once?
Yes. Upload a batch of FB2 files and they are all converted to MOBI. 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 MOBI?
Yes. MOBI 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 MOBI for?
MOBI is an Amazon ebook format best for older Kindle devices. Convert your FB2 to MOBI when your eReader or app opens MOBI more reliably, so the whole library works on one device.
What is FB2?
FB2 is the FictionBook ebook format, typically used for FictionBook readers. Converting it to MOBI produces a file that opens on systems without FB2 support.