AZW3 to EPUB: Move Kindle Books to Kobo, Apple Books or Nook

You bought a Kobo Clara, plugged it into your laptop, dragged the Documents folder off your old Kindle, and the new reader shows… nothing. Not a single title. The files are all there — The-Silent-Patient.azw3, SICP.azw3, forty more — and the Kobo acts like the drive is empty.

That isn't a bug. AZW3 (also called KF8) is Amazon's own container format, and Kobo, Apple Books, Nook, PocketBook and Tolino support exactly none of it. They all speak EPUB. So the fix is a format conversion: AZW3 to EPUB, done once, in bulk, with your covers and metadata surviving the trip.

One hard rule before we start: this only works on DRM-free files. More on how to tell in thirty seconds.

First: is your AZW3 file actually DRM-free?

Books bought from the Kindle Store are normally encrypted with Amazon's DRM. No converter — ours, Calibre's, anyone's — can open those, and stripping DRM from books you licensed is illegal in many countries. We're not covering it.

DRM-free AZW3 files are common all the same. They come from Humble Bundle, StoryBundle, itch.io, Leanpub, Smashwords, Standard Ebooks, most indie author sites, technical publishers like Pragmatic Bookshelf, and anything you emailed to your own Kindle via Send to Kindle.

Three quick ways to check a file:

• Open it in Calibre. Add the file to your library and click Edit book (or just preview it). If the text renders, it's clean. If Calibre throws DRMError: This book is DRM protected, stop there.
• Check where it came from. A file sitting in your Kindle's documents folder that you sideloaded yourself is almost certainly fine. One with a .azw extension and a matching .kfx sibling usually is not.
• Look at the size pattern. Not definitive, but DRM-free AZW3 files from bundle sites typically run 300 KB–4 MB for a novel; heavily illustrated technical books go 10–40 MB.

The fast route: convert AZW3 to EPUB online

If you have a handful of books and no desire to install anything, use the browser. Drop your files into our AZW3 to EPUB converter, wait for the conversion, and download EPUBs that Kobo, Apple Books and Nook open natively.

What the conversion carries over:

• Cover image, embedded as the EPUB cover so it shows on your Kobo home screen
• Title, author, publisher, language and ISBN from the AZW3 metadata block
• Table of contents and chapter breaks
• Italics, bold, blockquotes, footnote links and embedded fonts

What usually shifts a little: fixed-layout comics and cookbooks, complex tables, and any Kindle-specific typographic hints. Reflowable prose — the 95% case — comes out clean.

Then copy the .epub files to your Kobo's root folder or a Books folder over USB, eject, and the Kobo indexes them on the next wake. On Apple Books, drag them into the app or AirDrop them to your iPad. On Nook, drop them in My Files.

If your library is a mixed pile of MOBI, AZW, PRC and AZW3 files, the ebook converter hub covers the other formats too.

The power route: Calibre's ebook-convert command line

For a 200-book library, scripting beats clicking. Calibre ships a command-line tool called ebook-convert that does everything the GUI does.

On macOS it lives inside the app bundle, so add it to your path first:

export PATH="/Applications/calibre.app/Contents/MacOS:$PATH"

On Windows it's in C:\Program Files\Calibre2\. On Linux it's already on your path after the standard installer.

One book, with sane defaults

ebook-convert "SICP.azw3" "SICP.epub" \
  --output-profile kobo_aura_one \
  --preserve-cover-aspect-ratio \
  --epub-version 3

--output-profile kobo_aura_one tunes default font sizes and image scaling for a Kobo screen; use ipad3 for Apple Books or nook_color for Nook. --epub-version 3 gives you better typography support on modern Kobo firmware. A 2.1 MB AZW3 typically lands around 1.8–2.4 MB as EPUB — the size barely moves because the content is the same HTML and images.

Fixing metadata on the way through

Bundle files are notorious for junk metadata — author listed as unknown, title as the filename. Fix it during conversion instead of afterwards:

ebook-convert "book.azw3" "book.epub" \
  --title "The Pragmatic Programmer" \
  --authors "Hunt, Andrew & Thomas, David" \
  --series "Pragmatic Bookshelf" \
  --series-index 1 \
  --cover "cover.jpg" \
  --language en

Kobo reads --series and --series-index and will group the books on your home screen — something the Kindle never did well.

Converting the whole library at once

From the folder holding your AZW3 files:

for f in *.azw3; do
  ebook-convert "$f" "${f%.azw3}.epub" \
    --output-profile kobo_aura_one \
    --preserve-cover-aspect-ratio \
    --epub-version 3
done

PowerShell equivalent:

Get-ChildItem *.azw3 | ForEach-Object {
  ebook-convert $_.FullName ($_.BaseName + ".epub") --epub-version 3
}

Forty books take a couple of minutes. Any file that fails loudly with a DRM error is one you can't legally convert anyway — let the loop skip it and move on.

Three things that go wrong on Kobo (and the fix)

• The cover is missing on the home screen. Kobo sometimes caches a blank thumbnail. Delete the hidden .kobo-images folder on the device, eject, and let it rebuild. Re-converting with --preserve-cover-aspect-ratio prevents the squashed-cover version of this bug.
• Chapters run together with no table of contents. Add --level1-toc "//h:h1" to your ebook-convert command to rebuild the TOC from heading tags.
• Text is one giant paragraph or the margins are enormous. Add --change-justification left and --remove-paragraph-spacing --remove-paragraph-spacing-indent-size 1.5 to normalise the CSS the Kindle format baked in.

Your move-day checklist

The whole migration, start to finish:

• Copy the documents folder off your Kindle over USB and back it up somewhere else first.
• Sort the DRM-free files from the store purchases — try opening one in Calibre.
• Convert the clean ones to EPUB, online for a handful, with ebook-convert for a library.
• Spot-check two or three EPUBs: cover, author name, chapter jumps.
• Copy to the Kobo over USB, eject properly, and let it index.

Store purchases stay where they are — read them in the Kindle app. Everything you actually own moves with you. If you just want the conversion done without a terminal, the AZW3 to EPUB converter handles it in the browser.

FAQ

Can a Kobo read AZW3 files directly? No. Kobo supports EPUB, EPUB3, PDF, MOBI (on older models, poorly), CBZ, CBR and TXT. AZW3 is Amazon-only and always needs converting.

Will converting lose my highlights and notes? Yes. Annotations live in Amazon's sidecar files, not in the book. Export them from the Kindle app before you switch.

What about KFX files? KFX is Amazon's newer format and is almost always DRM-protected. Standard converters can't read it.

Is EPUB better quality than AZW3? Neither is inherently better — both wrap HTML and CSS. EPUB is the open standard, so it's the safer long-term container for a library you want to keep.

Does Apple Books need anything different? No. The same EPUB works on Kobo, Apple Books, Nook and PocketBook. Use --output-profile ipad3 if you're converting specifically for an iPad.

Can I convert on a phone? Calibre is desktop-only, but a browser-based converter works fine from iOS or Android — then use the Kobo app's import or a USB-C drive.