EPUB – Electronic Publication
EPUB is the open standard ebook format. Text reflows to fit any screen, and it is supported by nearly every e-reader except older Kindles.
More EPUB conversionsDrop your EPUB files here
or click to choose EPUB files · up to 95MB each
How to convert EPUB to AZW3
- Choose your files. Click Select File or drag your EPUB files into the upload box. You can add many at once.
- Pick the settings. AZW3 is already selected as the output format. The conversion starts as soon as a file is added.
- Download. Each file appears in the list when it is ready. Download them one by one, or all together with Download all.
Why convert EPUB to AZW3?
AZW3, also called KF8, is the modern Kindle format. Kindles cannot open EPUB files copied over USB, so converting EPUB to AZW3 lets you copy DRM-free books straight onto your Kindle with a cable and keep their formatting.
When to keep the EPUB
Keep the EPUB: it works in every other reading app and is the format to send with Send to Kindle.
Tips for the best result
- Connect the Kindle to your computer and copy the AZW3 into its documents folder.
- Chapters, table of contents, images and formatting are kept.
- Books bought from Kindle, Kobo or Google Play are usually DRM-protected and cannot be converted. DRM-free books, such as those from Project Gutenberg or many independent authors, work.
Common problems and fixes
- The book does not appear on my Kindle.
- Make sure the file is in the documents folder, then safely eject the Kindle so it can index the new book.
- The file will not convert.
- The EPUB is probably DRM-protected. Only DRM-free books can be converted.
AZW3 – Kindle Format 8
AZW3 (Kindle Format 8) is Amazon's newer ebook format with better typography and HTML5/CSS support than MOBI.
More AZW3 conversionsConverting EPUB to AZW3
- DRM-protected books cannot be converted. PDF input works best for text-based PDFs.
Related guide
- How to read EPUB books on KindleKindles do not open EPUB files directly. Learn the easiest way to send EPUB to Kindle, when to convert to AZW3 or MOBI, and why some books cannot be converted.
Frequently asked questions
AZW3 or MOBI for my Kindle?
AZW3 for any Kindle from the last ten years: it supports better layout. MOBI is only needed for very old models.
Can I use Send to Kindle instead?
Yes. Send to Kindle accepts EPUB directly, so you only need AZW3 when copying books over USB.
How do I convert EPUB to AZW3?
Click Select File or drop your EPUB file onto the upload box. The converted AZW3 appears in the list below with a download button. You can add many files at once and download them together as a ZIP.
Is it really free?
Yes. There is no sign-up and no watermark. To keep the service available for everyone there is a 95MB limit per file and a cap on how many files one connection can process in a short period.
Are my files stored?
Your upload is used only to make the converted file. Images are processed in memory; other files are written to a private temporary folder that is deleted as soon as the conversion finishes. Nothing is kept after the result has been sent back.
Will quality drop?
For images, a little, by design: the image is re-encoded at the Quality you choose (default 75%). Audio and video are re-encoded with high-quality settings; documents keep their text and layout as far as the target format allows. Converting never restores detail that is already missing from the original.
How this works: your file is uploaded over HTTPS and converted on this server with open-source engines (libvips for images, FFmpeg for audio and video, LibreOffice and Pandoc for documents, Calibre for ebooks, Ghostscript and Inkscape for PDF and vector files). Images are processed in memory; other files use a private temporary folder that is deleted as soon as the conversion finishes.