M4B to TXZ Converter
Processing entirely on your device — large files may take a moment.
Convert TXZ exactly like TAR.XZ. If your files are still in M4B format, this page is the shortcut: M4B is the audiobook flavour of M4A — AAC audio with chapter markers, used by Audible and Apple Books.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How M4B compares to TXZ
| M4B | TXZ | |
|---|---|---|
| Compression | Lossy AAC + chapters | XZ / LZMA2 |
| Quality | Speech-optimized bitrates | Lossless, deterministic |
| Best for | Chaptered audiobooks | Source releases, Linux packages |
How to convert M4B to TXZ
- 1
Select your files
Select your M4B file — it never leaves your device.
- 2
Convert instantly
The engine packs the file, byte for byte, into a TXZ container — no re-encoding, no quality change.
- 3
Download results
Download the finished TXZ archive.
About the M4B format
M4B is M4A wearing an audiobook badge: the same AAC audio in an MP4 container, plus chapter markers that Apple Books and Audible apps render as a scrubbing timeline. Buy an audiobook outside Audible and it likely arrives as M4B.
The format is deliberately chained to Apple's book ecosystem. Converting M4B to MP3 sets the book free: car stereos, gym players, old iPods and every app without chapter support will play it — though the chapter marks themselves are flattened away.
+Strengths
- ✓Chapter markers survive on Apple platforms
- ✓Efficient AAC audio
!Limitations
- −Chapters vanish in MP3 conversion
- −Non-Apple support is patchy
About the TXZ format
TAR.XZ pairs the tar container with XZ (LZMA2) compression — the highest-ratio member of the tar family and the de-facto release format of modern Linux distributions. The same source tree that lands 5% smaller than TAR.BZ2 and 20% smaller than TAR.GZ is why kernel.org and GNU mirrors standardised on it.
The trade is CPU time: XZ compresses slow (dictionary sizes up to 64 MB) but decompresses fast, which makes it ideal for one-time releases that get downloaded millions of times. When you need speed instead, TAR.GZ or TAR.ZSTD are the neighbouring picks.
+Strengths
- ✓Best compression ratio of the tar family
- ✓Standard release artifact of Linux distros
- ✓Fast decompression despite slow compression
!Limitations
- −Compression is CPU-heavy and single-threaded by default
- −Larger toolchain footprint than gzip on tiny systems
Why convert M4B to TXZ?
Converting makes sense where the strengths of TXZ meet what M4B cannot give you. Best compression ratio of the tar family Meanwhile Chapters vanish in MP3 conversion One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this M4B to TXZ 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 M4B to TXZ?
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.
Will converting M4B to TXZ reduce audio quality?
If TXZ is lossless, the output contains everything the M4B file contains — no further loss is added. If TXZ is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.
Can I convert a whole folder of M4B files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.