What is a .azw file? (AZW)

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.

How to open 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. For a step-by-step walkthrough, see how to open a .azw file.

Windows

Kindle app
Calibre
Kindle Previewer

macOS

Kindle app
Calibre

Linux

Calibre

Web

Kindle Cloud Reader

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.

.azw file signature (magic bytes)

Programs recognise a .azw file by the bytes at the start of the file, not by its name. These are the signatures for AZW. For a full breakdown, see the AZW file signature page.

Hex signature	Offset	Note
42 4F 4F 4B 4D 4F 42 49	60	'BOOKMOBI' (Palm database)

See the full magic-numbers reference for every format.

Frequently asked questions

What is a .azw file?

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

Details on this page were checked against authoritative references:

Wikipedia: Kindle File Format