Convert MOBI to FictionBook Online Free
Convert MOBI ebooks to FictionBook FB2 format for use in FBReader, CoolReader, and other FB2-native reading apps. Powered by Calibre.
ChangeThisFile converts your MOBI ebook to the open FictionBook FB2 format using Calibre on our secure servers. FB2 is the dominant ebook format in Russia and Eastern Europe, supported by FBReader and CoolReader with superior typography controls. Chapter structure, cover art, and metadata are preserved. Your file is encrypted in transit and auto-deleted after conversion, free with no signup.
Convert MOBI to FictionBook
Drop your MOBI file here to convert it instantly
Drag & drop your .mobi file here, or click to browse
Convert to FictionBook instantly
MOBI vs FictionBook: Format Comparison
Key differences between the two formats
| Feature | MOBI | FictionBook (FB2) |
|---|---|---|
| Developer | Mobipocket SA / Amazon | Open XML community standard |
| Structure | Proprietary binary format | Open single-file XML document |
| Primary use | Kindle devices and apps | FBReader, CoolReader, Russian ebook platforms |
| Metadata | Basic Amazon metadata fields | Rich XML header (title, author, genre, series) |
| DRM | Amazon DRM possible | No DRM support |
| Open standard | No (proprietary) | Yes |
| File type | Single binary file | Single XML file |
When to Convert
Common scenarios where this conversion is useful
Access Kindle books in FBReader
FBReader offers more typography and layout customization than the Kindle app. Converting DRM-free MOBI files to FB2 lets you read your Kindle library with FBReader's advanced reading controls on Android and desktop.
Migrate away from Amazon's ecosystem
MOBI is a proprietary Amazon-centric format. Converting to the open FB2 standard ensures your ebook library remains accessible without dependency on Amazon's software or services.
Russian and Eastern European reading platforms
Many ebook services and reader communities in Russia distribute and expect FB2 files. Converting your MOBI ebooks to FB2 makes them compatible with these platforms and their library tools.
How to Convert MOBI to FictionBook
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1
Upload your MOBI file
Drag and drop your .mobi file onto the converter, or click to browse. Files up to 50 MB are supported for free.
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2
Server-side conversion
Your file is securely uploaded to our servers where Calibre reads the MOBI content and converts it to FictionBook XML, mapping chapters, metadata, and images to their FB2 equivalents.
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3
Download the result
Once conversion is complete, click Download to save your .fb2 file. Your uploaded file is automatically deleted from our servers.
Frequently Asked Questions
MOBI is a proprietary Amazon format limited to Kindle devices and apps. FictionBook is an open XML standard with wide support in FBReader, CoolReader, and Russian ebook platforms, giving you more reading flexibility.
Yes, completely free. Convert MOBI to FB2 with no cost, no signup, and no watermarks.
Yes. Calibre maps MOBI's internal chapter markers to FictionBook section elements, preserving the book's structure and table of contents in the FB2 output.
Yes. Cover art from the MOBI file is embedded as a Base64 binary object in the FB2 XML, where FB2-compatible readers display it on the title page.
Yes. Calibre transfers title, author, publisher, and series metadata from the MOBI file to the corresponding FictionBook XML header fields.
No. Files protected with Amazon DRM cannot be converted. Only DRM-free MOBI files are supported.
FB2 is natively supported by FBReader (Android, Linux, Windows), CoolReader (Android, Windows), and many other apps. It is not supported by Kindle or Apple Books without conversion.
No. Files are automatically and permanently deleted from our servers immediately after conversion. We retain no ebook content.
Yes. All file transfers use HTTPS encryption. Your data is protected in transit between your device and our conversion servers.
The conversion uses Calibre, the open-source ebook management tool, running on our secure servers.
Files up to 50 MB are supported for free. Most MOBI ebooks are well under this limit.
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