CONVERT
EPUB → PDB
Fast, secure EPUB 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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Here is the short version — EPUB is the open IDPF ebook standard, a ZIP of HTML and CSS supported by every modern e-reader. Hence the need for PDB. Our EPUB 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. Context: EPUB is the open IDPF ebook standard, a ZIP of HTML and CSS supported by every modern e-reader. PDB is an ebook format tuned for reflowable reading on e-readers and mobile devices.
EPUB eBook
Source formatEPUB is the open standard for reflowable digital books. It adapts text to any screen size and is supported by most e-readers except Kindle. EPUB 3 adds support for multimedia and interactivity.
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 EPUB to PDB
PDB works on your specific reader where EPUB 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
EPUB → PDB
Upload the EPUB
Drop the ebook file into the uploader. We detect the format and extract metadata automatically.
Convert through Calibre
Calibre parses the EPUB 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 EPUB library once for smooth sideload.
Kobo / e-ink readers
Third-party e-ink readers prefer PDB; EPUB may open but without reflow or chapter navigation.
Library consolidation
Merge EPUB and PDB collections into a single PDB library for cleaner search, tagging and sync.
Self-publishing pre-flight
Validate a manuscript across both EPUB and PDB targets before submitting to retailers.
Quality & Compatibility
Text content is preserved losslessly — every word of the EPUB ends up in the PDB. Formatting richness depends on what the PDB container supports; heavy typography that works in EPUB 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 EPUB probably had a weak ToC — Calibre respects what it finds, it cannot invent structure that was not there.
- For fixed-layout EPUB (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 EPUB 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 EPUB 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 EPUB 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 EPUB 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.