What is a .azw3 file?
Kindle Format 8 (KF8) · eBook · Amazon · 2011
AZW3, also called Kindle Format 8, is Amazon's eBook format for Kindle and the successor to MOBI. It supports modern styling and reflowable text, and it is tied to the Kindle ecosystem, so it opens best in a Kindle app or through Calibre.
What is a .azw3 file used for?
AZW3 replaced the old MOBI format on Kindle, adding proper CSS styling, embedded fonts and better layout while keeping the reflowable text that makes eBooks adapt to any screen.
Books bought from the Kindle Store usually carry DRM that ties them to your Amazon account, so they open only in Kindle apps signed in to that account.
DRM-free AZW3 files open in Calibre, which also converts them to and from EPUB. Amazon now accepts EPUB directly through Send to Kindle, converting it on the way in.
What opens a .azw3 file?
The .azw3 format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- Kindle app
- Calibre
macOS
- Kindle app
- Calibre
Linux
- Calibre
- Foliate
Web
- Kindle Cloud Reader (for purchased books)
Open a .azw3 file step by step
- Confirm the file really is a .azw3. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with Kindle app or Calibre.
- On Mac, use Kindle app or Calibre.
- On Linux, try Calibre or Foliate.
- Still stuck? Convert the .azw3 to EPUB, which opens more widely.
Why can't I open my .azw3 file?
Almost always because no installed app understands AZW3. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .azw3 at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .azw3 file
You can convert a .azw3 file to EPUB, PDF, MOBI using a conversion tool or the export menu of an app that opens it.
AZW3 has no fixed magic number, so there is no signature table on this page. Its bytes alone do not prove the format: identification relies on the extension, the structure of the content and the program that created it. The magic-numbers reference lists the formats that do carry one.
Frequently asked questions
What is a .azw3 file?
AZW3, also called Kindle Format 8, is Amazon's eBook format for Kindle and the successor to MOBI. It supports modern styling and reflowable text, and it is tied to the Kindle ecosystem, so it opens best in a Kindle app or through Calibre.
How do I open an AZW3 file?
Read it in a Kindle app, or open a DRM-free one in Calibre. Books bought from Amazon are tied to your account and open only in Kindle apps signed in as you.
How do I convert AZW3 to EPUB or PDF?
Use Calibre: add the file and convert it to EPUB or PDF. This works for DRM-free files; books still protected by Amazon's DRM cannot be converted.
Related formats
Sources
Details on this page were checked against authoritative references. How sources are ranked and what is deliberately left out is set out in the methodology.