What is a .azw file?
Amazon Kindle eBook · eBook · Amazon · 2007
An .azw file is a Kindle eBook, Amazon's format based on Mobipocket. It holds a reflowable book and often carries DRM tied to your Amazon account, which is the usual reason it will not open elsewhere.
What is a .azw file used for?
AZW is a Palm database like MOBI, so the marker BOOKMOBI sits at offset 60. Newer Kindle books use AZW3 (KF8) or KFX. A DRM-free AZW opens in many readers; a DRM-protected one only works in Kindle apps on your account.
To read an AZW on other devices, use a Kindle app, or convert a DRM-free copy to EPUB with Calibre.
What opens a .azw file?
The .azw 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
- Kindle Previewer
macOS
- Kindle app
- Calibre
Linux
- Calibre
Web
- Kindle Cloud Reader
Open a .azw file step by step
- Confirm the file really is a .azw. 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.
- Still stuck? Convert the .azw to epub, which opens more widely.
Why can't I open my .azw file?
Almost always because no installed app understands AZW. 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 .azw 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 .azw file
You can convert a .azw file to epub, pdf, mobi using a conversion tool or the export menu of an app that opens it.
What is the .azw file signature (magic bytes)?
A .azw file carries the hex bytes 42 4F 4F 4B 4D 4F 42 49 at offset 60, which read as BOOKMOBI in ASCII. Programs identify AZW by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for AZW. For a full breakdown, see the Mobipocket file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 42 4F 4F 4B 4D 4F 42 49 | 60 | BOOKMOBI | 'BOOKMOBI' (Palm database) |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .azw file?
An .azw file is a Kindle eBook, Amazon's format based on Mobipocket. It holds a reflowable book and often carries DRM tied to your Amazon account, which is the usual reason it will not open elsewhere.
How do I open an .azw file?
Use a Kindle app on any device, or Calibre for DRM-free books. Books bought from Amazon are usually locked to your account.
Why won't my .azw open on another e-reader?
Most Amazon AZW files carry DRM tied to your Kindle account, so only Kindle apps read them. A DRM-free AZW opens more widely.
How do I convert AZW to EPUB?
Import a DRM-free .azw into Calibre and convert to EPUB. DRM-protected books cannot be converted.
Related formats
Sources
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