Free Online EPUB to AZW3 Converter

Convert EPUB to AZW3 online for free.

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EPUB to AZW3: the Kindle that reflows properly

AZW3 is Amazon’s KF8 format, and unlike the older MOBI it understands most of the CSS an EPUB carries, embedded fonts, drop caps, fixed layout, tables that survive. The conversion rewrites the EPUB’s XHTML and styles into the KF8 structure and repacks it. Content and structure carry across; what will not is anything the Kindle renderer has no equivalent for, such as JavaScript or SVG filters.

Convert when you are sideloading onto a Kindle and want the book to look close to the EPUB rather than flattened. Prefer AZW3 over MOBI for anything with real typography; MOBI only if the device is old enough to require it.

EPUB vs AZW3: Side-by-side

Technical comparison of the two formats, useful for deciding which to use, or for confirming what changes during conversion.

Property	EPUB	AZW3
Full name	Electronic Publication	Kindle Format 8
Year introduced	2007	2011
Developer / standard body	W3C (formerly IDPF)	Amazon
MIME type	application/epub+zip	application/vnd.amazon.ebook
File extension	.epub	.azw3
Compression	ZIP-compressed XHTML + CSS	Variable
Color / data depth	N/A	N/A
Max dimensions / size	Software-limited	Software-limited
Transparency	No	No
Animation	No	No
Standard / specification	W3C EPUB 3.3 / ISO/IEC 23736	Amazon
Best for	Apple Books, Kobo, Nook, Google Play Books, reflowable text	Modern Kindle devices, enhanced typography and layout

Frequently asked questions

Can I convert EPUB books to AZW3 for my Kindle or Kobo?

Yes. Upload your EPUB ebook and it converts to AZW3 with chapter structure, cover art, and formatting preserved. Load the AZW3 onto your Kindle, Kobo, Nook, or any eReader that supports the format.

How to convert EPUB to AZW3 without losing the table of contents

Chapter navigation, the cover image, and text formatting all carry over during conversion. The AZW3 has proper chapter links so you can jump between sections on your eReader just like the original EPUB.

Can I convert multiple EPUB ebooks to AZW3 at once?

Yes. Upload a batch of EPUB files and they are all converted to AZW3. Each book downloads separately or as a ZIP, so you can convert an entire library in one session.

Does the text still reflow after converting to AZW3?

Yes. AZW3 keeps text reflowable, so it adapts to any screen size and font setting on your eReader rather than being locked to a fixed page like a PDF.

Which reader is AZW3 for?

AZW3 is the AZW3 format best for its intended use. Convert your EPUB to AZW3 when your eReader or app opens AZW3 more reliably, so the whole library works on one device.

What is EPUB?

EPUB is a reflowable ebook format, typically used for Kobo, Apple Books, and Nook. Converting it to AZW3 produces a file that opens on systems without EPUB support.