EPUB to AZW3
Converter

Convert EPUB to AZW3 online for free. Upload your EPUB file and download the AZW3 in seconds — private, browser-based, no signup, nothing to install.

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Text-to-Speech Document Reader Scanned PDF eBook to Flipbook

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ReadLoudly text to speech reader: pasted text on the left, the spoken text with highlighting on the right, voice, speed and pitch controls above and a play bar below — Press **Listen** and your text opens in the ReadLoudly reader — pick a voice, set the speed, follow the highlighted words. Free, no signup.

Click to upload, or drag and drop

EPUB files files up to 50MB each

Supported formats: EPUB files

UPLOAD

SETTINGS

RESULT

AZW3 Output Options

Input profile

Output profile

EPUB version

Base font size (pts)

Font size mapping

MARGINS (CM)

top

bottom

left

right

Flatten EPUB Flatten EPUB structure before conversion (useful for malformed EPUBs).

How To Convert?

Convert your files quickly and securely.

Upload Your File

Choose the EPUB file you want to convert, or drag it onto the page.

Adjust the Settings

Set your options, then click Convert EPUB to start.

Download the Result

Click Download AZW3 to get your new file.

About EPUB to AZW3 Conversion

What is the EPUB format?

EPUB stands for Electronic Publication — the open ebook standard maintained by the W3C. It is used by readers of Kobo, Apple Books, Google Play Books and most non-Kindle devices. Its strengths are text that reflows to any screen size, adjustable fonts, chapters and metadata; its drawback is that Kindle devices and many office tools cannot open it directly.

What is the AZW3 format?

AZW3 stands for Kindle Format 8 (KF8) — Amazon's 2011 successor to MOBI, built on HTML5 and CSS3. It is used by anyone reading on a Kindle Paperwhite, Oasis or the Kindle app. Its strengths are embedded fonts, tables, drop caps, fixed-layout comics and richer typography than MOBI; its drawback is that only Kindle software reads it natively, so files cannot be shared with other e-readers.

What changes when you convert EPUB to AZW3

EPUB and AZW3 are both reflowable ebook formats, so the conversion keeps chapters, the table of contents, cover art, metadata and inline images; what changes is which devices can open the file. Styling that AZW3 does not support is simplified rather than dropped, and DRM-protected EPUB files cannot be converted at all.

Leaving EPUB behind means leaving behind its main drawback: Kindle devices and many office tools cannot open it directly. What you get in return is what AZW3 does best — embedded fonts, tables, drop caps, fixed-layout comics and richer typography than MOBI — which is why anyone reading on a Kindle Paperwhite, Oasis or the Kindle app rely on it. Tip: send the finished AZW3 to your Kindle by email or USB; if the book has a cover, it is embedded so it shows in your library.

The conversion itself runs with Calibre and ImageMagick on encrypted servers. Files are deleted automatically once the AZW3 has been generated — nothing is stored or read — and no account is needed.

Why convert EPUB to AZW3?

Read the book on a device or app that does not support EPUB
Keep bookmarks, progress and highlights in your usual ebook reader
Fix a library where the same book exists in several formats
Listen to it: open the AZW3 in the ReadLoudly reader and have it read aloud

EPUB to AZW3 — Frequently Asked Questions

Everything worth knowing before you convert a EPUB file to AZW3.

How do I convert EPUB to AZW3 online?

Upload your EPUB above, adjust any EPUB-to-AZW3 options you need, and press Convert. The finished AZW3 is ready to download as soon as processing completes — no software to install and no account required.

Is the EPUB to AZW3 converter free?

Yes. EPUB to AZW3 conversion is free with no signup, and there is no watermark on the output. Signing in raises the file size limit and puts your jobs into the priority processing queue.

Is there a file size limit for EPUB files?

Guests can convert an EPUB of up to 50 MB into AZW3. Signed-in users get higher ceilings — 200 MB on Core, 350 MB on Plus and 500 MB on Pro — which matters most when the source EPUB is image-heavy or book-length.

What happens to my EPUB file after conversion?

Your EPUB upload is encrypted in transit, converted, and then deleted automatically along with the AZW3 output. ReadLoudly does not read, retain long-term, train on, or share the contents of a EPUB file you convert here.

How long does a EPUB to AZW3 conversion take?

Most EPUB files finish in under 30 seconds. A large, image-heavy or multi-hundred-page EPUB can take a minute or two before the AZW3 is ready — the page updates on its own, so there is no need to refresh or resubmit.

Can I listen to the AZW3 file after converting it?

Yes. Open the converted AZW3 in ReadLoudly's AZW3 reader and it can be narrated with 1200+ AI voices across 40+ languages. Going EPUB to AZW3 first is often the whole point — it puts the content into a format the reader handles natively.

Do I need Calibre installed to convert EPUB to AZW3?

No. ReadLoudly runs the EPUB to AZW3 conversion on its own servers with the same industry-standard tooling (Calibre and ImageMagick) you would otherwise install yourself, so it behaves identically on Windows, macOS, Linux, iOS and Android straight from the browser.

Guides and comparisons from the ReadLoudly blog on getting more out of listening to your documents.