EPUB to AZW3 Converter
AZW3 is the Kindle's own layout format, the one that keeps embedded fonts and CSS styling. Convert a DRM-free EPUB to AZW3 when you copy books to a Kindle by cable and want them to look as the designer intended.
E-book Converter
or drop EPUB, MOBI, AZW … files here ·
Max 95 MB per file· Up to 20 files· Deleted after 30 minutes
Files are processed on our servers and deleted after 30 minutes.
0 keeps the book's own size. E-readers let the reader change size anyway; this mainly matters for PDF, DOCX and TXT output.
Space around the text on each page. 5 mm suits e-ink screens; use 15–20 mm for a PDF you plan to print.
Justified text has straight edges on both sides like a printed book; left-aligned avoids wide gaps between words on small screens.
A5 is close to a paperback and reads well on tablets. Match device sizes the page to the reading device chosen above.
Keep the book's cover, use the first image as the cover (comics and photo books), or leave the book without one.
JPEG quality for pictures and comic pages. 85 looks identical on e-ink; lower it to shrink large comics.
Leave empty to keep the title stored in the file. This is the name shown in the reader's library.
Leave empty to keep the existing author.
How to use this tool
- 1
Upload EPUB files
Pick up to 20 DRM-free .epub books, each up to 95 MB. EPUB 2 and EPUB 3 files are both read.
- 2
Choose your Kindle
Reading device starts at Kindle Paperwhite / Oasis. Pick Kindle Scribe or the basic Kindle if that is what you read on; it changes image sizing and page breaks.
- 3
Convert and copy over USB
Press Convert to AZW3, plug in the Kindle and drop the file into its documents folder. Uploads are deleted after 30 minutes.
Should I convert EPUB to AZW3 or just email the EPUB to my Kindle?
Email the EPUB if you want sync across devices. Convert to AZW3 when you copy books over USB, manage them in Calibre or want embedded fonts and styling kept exactly.
AZW3 vs MOBI vs EPUB on a Kindle
| AZW3 (KF8) | MOBI | EPUB via Send to Kindle | |
|---|---|---|---|
| Delivery | USB cable | USB cable | Email, app or website |
| Embedded fonts | Yes | No | Converted by Amazon |
| CSS styling | Most of CSS3 | Basic HTML only | Converted by Amazon |
| Syncs position across devices | No | No | Yes |
| Works on Kindle 1, 2, DX | No | Yes | No |
| Needs an Amazon account | No | No | Yes |
Amazon introduced Kindle Format 8 in 2011 to bring HTML5 and CSS3 layout to Kindles, and AZW3 is the file extension it gets outside the store. It supports the things EPUB 3 books lean on: embedded typefaces, fixed-position images, tables, drop caps and nested lists. Under the hood the converter turns each XHTML chapter into Kindle markup, keeps the stylesheet rules KF8 understands and rebuilds the navigation so chapters appear under Go To.
Calibre, the open-source library manager Kovid Goyal has developed since 2006, made EPUB to AZW3 the standard sideloading path, and this page follows the same approach. If something looks off, Amazon's free Kindle Previewer shows the file as it will appear on different Kindle models before you copy it.
EPUB
Electronic Publication
EPUB is the open ebook standard, first published by the International Digital Publishing Forum in 2007 and now maintained by the W3C. It packages XHTML, CSS, images and metadata in a ZIP file, so text reflows to fit any screen size and font setting. EPUB 3 adds audio, video, fixed layouts and accessibility features. Apple Books, Kobo, Google Play Books and most reading apps open EPUB, and Kindle accepts it through Send to Kindle.
- Compression
- –
- Transparency
- –
- Animation
- –
- Introduced
- 2007 · IDPF (now W3C)
AZW3
Kindle Format 8 (AZW3)
AZW3, also called KF8, is the Kindle ebook format Amazon introduced in 2011. It is based on HTML5 and CSS3, so it supports embedded fonts, better layouts and richer formatting than MOBI. Books bought from the Kindle Store may be wrapped in DRM, but DRM-free AZW3 files can be read in Calibre and sent to Kindle devices. Non-Amazon e-readers and apps generally do not support it.
- Compression
- –
- Transparency
- –
- Animation
- –
- Introduced
- 2011 · Amazon
EPUB to AZW3 is the sideloading route for Kindle owners who keep their own library, keeping the book's typography on the device without going through Amazon's conversion service.
How to put an AZW3 file on a Kindle
Convert
Upload the EPUB here and download the .azw3 file.
Connect
Plug the Kindle into a computer; it mounts as a drive named Kindle.
Copy and eject
Drop the file into the documents folder, eject, and it appears in the library.
What changes when an EPUB becomes AZW3
Body text, headings, images and links come across unchanged. Some EPUB 3 features have no Kindle equivalent: audio and video clips are dropped, JavaScript is ignored, and complex SVG drawings may be flattened. Fixed-layout EPUBs, such as picture books and comics laid out page by page, convert best with Reading device set to the model you own so images are sized to its screen.
If you have an EPUB that only needs to reach a Kindle and you do not care which route, the EPUB to Kindle page sets everything up for the Kindle defaults in one step.
EPUB to AZW3 questions
Is AZW3 better than sending the EPUB with Send to Kindle?
For most people Send to Kindle is easier: email or upload the EPUB and Amazon converts and syncs it, as our guide on sending EPUB to Kindle explains. AZW3 wins when you want no Amazon account involved, when a book's embedded fonts or styling get flattened by Amazon's conversion, or when you manage your library in Calibre.
Why don't my sideloaded AZW3 books sync reading position?
Whispersync works for books in your Amazon account. A file copied over USB lives only on that one Kindle, so position, highlights and notes stay on the device. Use Send to Kindle if sync across devices matters to you.
The cover shows as a gray placeholder in my Kindle library. Why?
Some Kindle firmware versions show generic covers for sideloaded books when the library thumbnail is missing or the book lacks an Amazon identifier. Keep Cover set to Keep so the cover image is stored in the book; it still appears when you open it, and Calibre users can regenerate thumbnails from the device menu.
Can I upload an AZW3 to Kindle Direct Publishing?
No. KDP takes EPUB, DOCX and KPF for e-books and builds its own Kindle files. Upload the EPUB itself for publishing, and use AZW3 only for reading or proofing on your own device.
Which Kindles cannot read AZW3?
The original Kindle, the Kindle 2 and the Kindle DX never received KF8 support. For those three, convert with EPUB to MOBI instead. Every Kindle e-reader released from 2011 onward reads AZW3.
