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AZW3 to EPUB converter

AZW3 to EPUB rebuilds a zipped EPUB package from Kindle KF8 content; protected Kindle purchases still fail.

  • Converted with Ebook engine · input deleted within 24 h
  • Free: 5 conversions a day · 5 MB each
  • Higher limits →

From real runs

What you get — and what changes

  • Encryption Lost

    DRM-protected Kindle books are outside this path; our ebook engine only converted the unencrypted fixture and generated test AZW3.

  • EPUB package Changed

    Our ebook engine wrote a new EPUB archive with content.opf at the root instead of the original API EPUB folder layout.

  • Cover Changed

    The output EPUB included cover_image.jpg even when the source AZW3 came from a small generated document.

  • Navigation Kept

    toc.ncx was present in the converted EPUB and listed the same chapter names from the rich round-trip fixture.

  • EPUB 3 nav Lost

    No nav.xhtml appeared in the AZW3-derived EPUB, so EPUB 3 navigation was downgraded to NCX-style navigation.

  • Metadata Kept

    The generated AZW3 returned title Rich QA EPUB and creator FTC Writer QA in OPF metadata.

Sample conversions

Round-tripped rich AZW3

Input
14,585 byte AZW3 generated from an API EPUB containing two chapters, a PNG, a footnote, and OPF author metadata.
Output
31,899 byte EPUB with toc.ncx, images/00001.png, cover_image.jpg, and the expected title and creator metadata.

Fixture AZW3 report

Input
14 KB sample AZW3 with the visible report heading Feedback Atlas and sparse title and author fields.
Output
32,194 byte EPUB with toc.ncx entries for Unknown, Feedback Atlas, Headline numbers, What went well, and Title Page.

A real AZW3 → EPUB run

We converted our AZW3 sample (14 KB) with Ebook engine on 2026-09-11. It took 344 ms and produced a 19 KB EPUB file, 1.3× larger than the input. The engine raised no warnings.

Input · sample.azw3 · 14 KB

Palm database, BOOKMOBI (KF8), title “Unknown”

Identifier
BOOKMOBI
Title
Unknown

Output · sample.epub · 19 KB

EPUB 2.0: 6 content documents, 1 image, NCX toc, cover set, title “Unknown”

Version
2.0
Content documents
6
Images
1
Table of contents
NCX toc
Cover
cover set
Title
Unknown

Do it yourself

Calibre ebook-convert

bash
ebook-convert in.azw3 out.epub

Calibre can rebuild an EPUB from unencrypted KF8 content, but it cannot recover Kindle annotations or remove encryption.

AZW3 to EPUB by API or MCP

The HTTP API and the MCP server run the exact engine this page uses (Ebook engine); the response carries the same warnings the web converter shows. Check support first with GET /api/v1/pairs?from=azw3&to=epub.

curl
curl -X POST https://filetypeconverters.com/api/v1/convert \
  -H "Authorization: Bearer $FTC_API_KEY" \
  -F "file=@input.azw3" -F "from=azw3" -F "to=epub" \
  --output output.epub
API reference

When this is the wrong conversion

  • Use /convert/azw3-to-mobi only when an older Kindle workflow demands MOBI instead of EPUB.
  • Use /convert/azw3-to-pdf if the next step is printing or page review rather than ebook editing.
  • Do not use this for Kindle store files unless you know the file is unencrypted.

AZW3 to EPUB questions

Why did AZW3 to EPUB add a cover image?

Our ebook engine creates EPUB cover landmarks while rebuilding the package. In our round-trip, the EPUB had both the original PNG content and a generated cover_image.jpg.

Does the converted EPUB include nav.xhtml?

Not in the files we inspected. The converted EPUB used toc.ncx navigation instead, so modern EPUB 3 nav data was not restored.

Can I convert a Kindle purchase this way?

Only if it is not DRM-protected. Encrypted AZW3 files fail, and this service does not provide decryption or circumvention.

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