MOBI to GZ Converter
Processing entirely on your device — large files may take a moment.
Kindle eBook and Gzip Compressed File exist for different jobs: MOBI is Amazon Kindle’s legacy e-book format (also AZW/AZW3). It predates EPUB adoption and still circulates in older book collections. Unpack a .gz into a normal file or repack it as ZIP/TAR when the receiving tool does not understand gzip.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How MOBI compares to GZ
| MOBI | GZ | |
|---|---|---|
| Layout | Reflowable, dated engine | One compressed member |
| Bundling | Single self-contained file | Single file |
| Best for | Legacy Kindle devices | Logs, dumps, datasets |
How to convert MOBI to GZ
- 1
Select your files
Select your MOBI file.
- 2
Convert instantly
The file bytes are gzip-compressed in place — the same archive your server or build tool produces, made locally.
- 3
Download results
Download the .gz file — ready to upload, serve or attach.
About the MOBI format
MOBI is the Mobipocket format Amazon adopted for the original Kindle (2007), later extended as KF8/AZW3. It reflows text like EPUB but with a fraction of the formatting capability — basic styles, images, bookmarks — and its metadata model is decades old. Amazon stopped accepting MOBI uploads for reflowable ebooks in 2022 in favor of EPUB.
Its remaining role is old hardware: early Kindle models and some e-readers that never learned EPUB. Note that DRM-protected Kindle books (AZW/KFX with encryption) are a separate, legally distinct matter from converting MOBI files you created or that are DRM-free.
+Strengths
- ✓Supported by legacy Kindle hardware
- ✓Compact and self-contained
!Limitations
- −Deprecated by Amazon since 2022
- −Weak formatting compared to EPUB3
- −Modern Kindle models prefer EPUB/AZW3
About the GZ format
A .gz file is one file squeezed by gzip — not an archive. kernel.org tarballs are “tar inside gz”, but plenty of logs, JSON dumps and CSV exports travel as plain .gz. Opening one means decompressing it back to the original bytes.
Repacking into ZIP or TAR gives the decompressed file a container that every GUI tool opens without a second thought.
+Strengths
- ✓Everywhere on Linux and macOS
- ✓Fast, well-understood compression
- ✓Streams natively from any tool
!Limitations
- −Single file only — no directory tree
- −No encryption or integrity metadata
Why convert MOBI to GZ?
There is a concrete reason this conversion exists: Deprecated by Amazon since 2022 GZ sidesteps that — Everywhere on Linux and macOS If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this MOBI to GZ converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for MOBI to GZ?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
What about folders and directory structure?
The full directory tree is preserved: folders stay folders, and deep paths arrive exactly as they were packed in the MOBI file.
Are the files inside my MOBI archive modified?
No. Contents are unpacked in memory and repacked into GZ byte-for-byte — the conversion changes the container, never the files inside it.