XZ Utils

XZ Utils is free general-purpose data compression software with a high compression ratio. XZ Utils were written for POSIX-like systems, but also work on some not-so-POSIX systems. XZ Utils are the successor to LZMA Utils.

The core of the XZ Utils compression code is based on LZMA SDK, but it has been modified quite a lot to be suitable for XZ Utils. The primary compression algorithm is currently LZMA2, which is used inside the .xz container format. With typical files, XZ Utils create 30 % smaller output than gzip and 15 % smaller output than bzip2.

XZ Utils consist of several components:

While liblzma has a zlib-like API, liblzma doesn't include any file I/O functions. A separate I/O library is planned, which would abstract handling of .gz, .bz2, and .xz files with an easy to use API.

Source code

The files have been signed with this OpenPGP key.

See the NEWS file for a summary of changes between versions.


5.2.5 was released on 2020-03-17.

The packages of the stable XZ Utils releases are hosted on Sourceforge and thus some of the links below redirect to the XZ Utils files section on Sourceforge. This means that if you use a web browser (detected from the user agent), you will see the Sourceforge download page before the download starts. The redirection shouldn't affect users of GNU Wget and similar utilities.

xz-5.2.5.tar.gz (1750 KiB) signature
xz-5.2.5.tar.bz2 (1439 KiB) signature
xz-5.2.5.tar.zst (1156 KiB) signature
xz-5.2.5.tar.xz (1122 KiB) signature


The new APIs, command line options etc. in development releases should be considered unstable. Incompatible changes to unstable features may be done before they get included in a stable release.

5.3.2alpha was released on 2021-10-28. It adds MicroLZMA support that is needed for erofs-utils. 5.3.1alpha added the lzma_file_info_decoder() API which is a step towards adding a random access (seeking) API for .xz files.

xz-5.3.2alpha.tar.gz (1730 KiB) signature
xz-5.3.2alpha.tar.xz (1137 KiB) signature

Git repository

git clone https://git.tukaani.org/xz.git



Building the code from the git repository requires GNU Autotools. Here are the minimum versions that should work with XZ Utils; using the latest versions is strongly recommended:

In addition, po4a is needed for translated documentation. If po4a is missing, autogen.sh will fail at the end but the package can be built normally still; only the translated documentation will be missing.



Python 3.3 includes bindings for liblzma. A backport of these bindings are available for Python 2 in the backports.lzma package.

lzmaffi is another Python binding which adds random-access decompression support.

The original Python 2 binding for liblzma is PylibLZMA.


Perl bindings for liblzma: IO-Compress-Lzma and Compress-Raw-Lzma.


Haskell bindings.

Delphi and Free Pascal

Bindings and example programs for Delphi and Free Pascal are available here.

Pre-built binaries

Many free software operating systems already provide easy-to-install XZ Utils binaries. It doesn't make sense to provide links to all those here. Instead, binaries or links to websites providing binaries are listed here only for operating systems that don't have well-known repositories where users would get software like this.

If you have a website that provides up-to-date XZ Utils binaries for an operating system that meets the the criteria above, let me know and I will include a link here. Note that I won't host the binaries themselves without a good reason.


The Windows version of XZ Utils includes binaries for 32-bit and 64-bit x86. The binaries only depend on msvcrt.dll, which is available on Windows 98 and later out of the box.

xz-5.2.5-windows.zip (1463 KiB) signature
xz-5.2.5-windows.7z (696 KiB) signature


The DOS version of XZ Utils includes only the xz command line tool and some documentation. The xz tool should work e.g. on FreeDOS (also in DOSEMU), MS-DOS, and Windows 95/98/98SE/ME. This doesn't necessarily work in DOSBox at all, and at least some problems are expected under Windows XP Command Prompt (signal handling doesn't work).

Since the DOS version is naturally going to get very little testing, it is recommended to use the Windows version instead of the DOS version if you need xz under Windows 98 or later. It is likely that that the DOS version will be updated only occasionally.

5.2.0 and later have experimental support for 8.3 filenames. See xz-dos.txt in the binary package or dos/README.txt in the source package for details.

xz-5.2.5-dos.zip (255 KiB) signature

The package includes some copylefted code from DJGPP and CWSDPMI. The relevant source code is available from their home pages, and copies are also available below.

djlsr205.zip (2000 KiB)
djtst205.zip (1061 KiB)
csdpmi7s.zip (88 KiB)

Juan Manuel Guerrero has made a more complete port of XZ Utils to DOS. It also has support for short file names (8.3), but the naming method is different from the one found in 5.2.0 and later. It is available from DJGPP mirrors under /current/v2apps (e.g. xz-500b.zip for 5.0.0 binaries).

Old versions

Source and binary packages of old XZ Utils releases are available on a separate page.

Supported platforms

Below is an incomplete and somewhat vague (version numbers mostly missing) list of operating systems on which XZ Utils should work. The compiler(s) or toolchains are mentioned in parenthesis. GCC refers to GCC 3 or later. If you have additions or corrections, please email them to me.

[1] See also the platform-specific notes in the INSTALL file.

[2] 2010-09-22: HP ANSI C compiler crashes when compiling XZ Utils on PA-RISC. On Itanium there are no problems.

[3] On Solaris 8 and 9 one may need to pass ac_cv_prog_cc_c99= to configure if using Sun Studio.


The most interesting parts of XZ Utils (e.g. liblzma) are in the public domain. You can do whatever you want with the public domain parts.

Some parts of XZ Utils (e.g. build system and some utilities) are under different free software licenses such as GNU LGPLv2.1, GNU GPLv2, or GNU GPLv3.

See the file COPYING for more details.