Convert AZW3 to MOBI.
Turn a DRM-free AZW3 (KF8) ebook into MOBI for older Kindle devices and apps that only read the original Kindle format.
A step back for compatibility
AZW3 replaced MOBI on Kindles years ago. Converting back makes sense only for first-generation Kindles, some older reading apps and a few library systems.
What may change
MOBI has simpler formatting, so custom fonts, complex tables and some layout touches can be simplified. The text, chapters and images remain.
Size change
The MOBI is often slightly smaller than the AZW3.
How it works
- 01
Upload your AZW3
Drop a file or pick one from your device. Private by default.
- 02
Convert with Calibre
Calibre rebuilds the book in the older MOBI format.
- 03
Download
Grab your MOBI.
Readable on the oldest Kindles
Chapters and table of contents kept
Private uploads, auto-deleted after 1 hour
No watermark, no signup to try
Open-source Calibre engine
AZW3 to MOBI
This re-flows the book into MOBI, carrying chapters, the table of contents and images. Reflowable ebook formats adapt to the reader's screen and font size. Heavy fixed layouts (comics, textbooks) convert less cleanly.
Common questions
Is it free?+
Yes. Convert AZW3 to MOBI free. No signup and no watermark. Free covers 10 server conversions a day, up to 100 MB a file. Pro removes the daily limit and raises the file limit to 2 GB.
Is my file private?+
Your file is uploaded to a private bucket, converted on our own engine, and auto-deleted after 1 hour. It is never sent to a third-party converter.
Why go from AZW3 to MOBI?+
Only for older devices and apps. MOBI supports less styling than AZW3, so use it when a reader cannot open AZW3.
Does it work on Kindle Store purchases?+
Only on DRM-free files. DRM-protected books cannot be converted by FileWhirl or any legitimate converter.
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