CONVERT
MOBI → PDB
Fast, secure MOBI to PDB conversion. No registration required.
DRAG. DROP. DONE.
Upload any file and our engines will handle format detection automatically.
Max 100 MB · Free plan · No signup required
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Situation. MOBI is Amazon's legacy Mobipocket ebook format, the older Kindle delivery format. Solution: a PDB, produced below. Our MOBI to PDB converter uses the same Calibre engine that powers the bulk of the ebook world. Authors use it, bookstores use it, pirates (unfortunately) use it — it is the de-facto standard for ebook format conversion and we just expose it over a simple browser upload. Background. MOBI is Amazon's legacy Mobipocket ebook format, the older Kindle delivery format. Destination side, PDB is an ebook format tuned for reflowable reading on e-readers and mobile devices.
Mobipocket eBook
Source formatMOBI is the Mobipocket eBook format historically used by Amazon Kindle devices. While Amazon has moved to newer formats, MOBI remains relevant for older Kindles and legacy eBook libraries.
PalmDOC eBook
Target formatPDB (Palm Database) is a generic database format from the Palm OS era that was widely used for ebooks on Palm handheld devices. PalmDOC and Mobipocket both use PDB as their underlying container for storing text-based ebook content.
Why convert MOBI to PDB
PDB works on your specific reader where MOBI does not. Ebook formats are tied to ecosystems — PDB is Amazon-native, PDB is IDPF-standard and opens everywhere, pick the one that matches your device and convert the rest.
HOW TO CONVERT
MOBI → PDB
Upload the MOBI
Drop the ebook file into the uploader. We detect the format and extract metadata automatically.
Convert through Calibre
Calibre parses the MOBI structure, reflows content and writes a PDB with the appropriate CSS profile for the target readers.
Download the PDB
Grab the converted ebook; both files auto-delete within two hours of the job finishing.
Common Use Cases
Kindle sideloading
Amazon devices and apps accept PDB natively — convert your MOBI library once for smooth sideload.
Kobo / e-ink readers
Third-party e-ink readers prefer PDB; MOBI may open but without reflow or chapter navigation.
Library consolidation
Merge MOBI and PDB collections into a single PDB library for cleaner search, tagging and sync.
Self-publishing pre-flight
Validate a manuscript across both MOBI and PDB targets before submitting to retailers.
Quality & Compatibility
Text content is preserved losslessly — every word of the MOBI ends up in the PDB. Formatting richness depends on what the PDB container supports; heavy typography that works in MOBI may degrade gracefully in PDB, never lost entirely.
Tips for Best Results
- Set author and title metadata in Advanced before conversion; fixing it after sideloading to a reader is far more work.
- If chapter navigation feels off in the PDB, the source MOBI probably had a weak ToC — Calibre respects what it finds, it cannot invent structure that was not there.
- For fixed-layout MOBI (art books, technical manuals with diagrams) consider whether a reflowable PDB actually makes sense before converting.
Frequently Asked Questions
Frequently Asked Questions
Yes. The free tier accepts files up to 100 MB without registration, email capture or watermarks. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.
Yes, provided the MOBI itself has a well-formed ToC. Calibre reads the navigation structure and writes an equivalent ToC into the PDB. If the source lacks a ToC we can generate one from heading levels in Advanced → structure detection.
Uploads run over HTTPS, files are processed in isolated containers, and both the source MOBI and the PDB output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.
No. KaijuConverter does not strip digital rights management. DRM-free MOBI files — anything you authored yourself, public-domain classics, files from DRM-free retailers — convert without any restriction.
Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.
Yes. The cover is extracted from the MOBI and re-embedded in the PDB at device-appropriate dimensions. You can also override it in Advanced by uploading a custom cover image alongside the book file.
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Secure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 2 hours. We never read, share, or store your data.