Convert FB2 to MOBI — Free Online Converter
Convert FictionBook 2 (.fb2) to Mobipocket eBook (.mobi) online for free. Fast, secure document conversion with no watermarks or registration.
Conversion settings — add a file to adjust
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How to Convert
Upload your .fb2 file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .mobi file when it's ready.
About FictionBook to MOBI Conversion
FB2 (FictionBook 2) is the XML-based ebook format dominant in Russian-speaking countries, storing semantically structured text with embedded images and rich metadata. MOBI is the Mobipocket-based format that works on every Amazon Kindle device and app ever made. Converting FB2 to MOBI enables Russian and Eastern European ebook content to be read on any Kindle device, from the original 2007 model to current hardware.
This conversion bridges two distinct ebook ecosystems — the FB2-centric Russian digital reading market and Amazon's global Kindle platform. For readers who have both FB2 collections from Russian sources and Kindle hardware, this conversion unifies their reading experience.
Why Convert FictionBook to MOBI?
Amazon Kindle devices and apps do not support FB2 format. Readers with FB2 ebook collections who want to read on Kindle must convert to a Kindle-compatible format. MOBI is the most universally compatible Kindle format, working on every Kindle device from 2007 to present, including all Kindle apps on iOS, Android, Mac, and PC.
For Russian-language publishers targeting international audiences, MOBI conversion enables direct distribution to Kindle readers worldwide via sideloading and the Send-to-Kindle service, bypassing the need for Kindle Store publishing while reaching the world's largest ebook device ecosystem.
Common Use Cases
- Convert FB2 Russian fiction for reading on Kindle e-readers and Kindle apps
- Transform FB2 ebook collections from LitRes for Kindle sideloading via USB
- Convert FB2 technical books to MOBI for reading on Kindle during commutes
- Prepare FB2 content for distribution to Kindle readers via Send-to-Kindle email
- Convert FB2 language learning materials to MOBI for Kindle-based study
How It Works
Calibre parses the FB2 XML, extracting semantic content (sections, paragraphs, emphasis, images, metadata). The XML content is transformed to HTML for MOBI's Mobipocket container. FB2 sections become MOBI chapter navigation entries. Base64-encoded images are decoded, resized to Kindle specifications (max 127 KB per image for older devices), and stored as MOBI image records. Metadata (title, author, language, annotation) maps to MOBI header fields. The output uses standard PDB container format compatible with all Kindle firmware versions.
Quality & Performance
Text content, chapter structure, basic formatting (emphasis, sections, paragraphs), and images transfer cleanly. FB2's semantic markup translates well to MOBI's HTML subset. Cyrillic text renders correctly on Kindle devices with Russian language support. The main limitation is MOBI's simpler CSS compared to FB2's potential formatting — decorative elements and complex layouts simplify in the conversion. For standard fiction and non-fiction, the conversion produces an excellent reading experience on Kindle.
Device Compatibility
| Device | FictionBook | MOBI |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Tips for Best Results
- 1Verify Cyrillic rendering on your specific Kindle model after conversion
- 2For newer Kindles (2012+), consider AZW3 for richer formatting support
- 3Check image quality — large FB2 images may be compressed to fit MOBI size limits
- 4Review the table of contents on Kindle to verify chapter navigation is correct
- 5Test with a few books before batch-converting your entire FB2 collection
Related Conversions
FB2-to-MOBI conversion bridges the Russian ebook ecosystem and Amazon's Kindle platform, producing universally compatible Kindle files from FB2's semantic XML source.