Command-line utility for creating or verifying checksums using fast non-cryptographic algorithm xxHash.
xxHash is an Extremely fast Hash algorithm, processing at RAM speed limits. Code is highly portable, and produces hashes identical across all platforms (little / big endian). The library includes the following algorithms:
XXH32: generates 32-bit hashes, using 32-bit arithmetic
XXH64: generates 64-bit hashes, using 64-bit arithmetic
XXH3 (since v0.8.0): generates 64 or 128-bit hashes, using vectorized arithmetic. The 128-bit variant is called XXH128.
All variants successfully complete the SMHasher test suite which evaluates the quality of hash functions (collision, dispersion and randomness). Additional tests, which evaluate more thoroughly speed and collision properties of 64-bit hashes, are also provided.
What's new in 0.8.4
xxHash v0.8.4 is a general maintenance update, offering broader hardware acceleration, command line enhancements, and more predictable builds across platforms. No change to the API entry points. Faster performance with vectorization This release adds several vectorized implementations: for the RISC-V Vector extension and LoongArch LASX, together with improvements to the existing LSX implementation. On aarch64, XXH3 now prefers NEON over SVE. On tested processors, this improves performance by 25–40%. XXH3 streaming performance has also been improved for workloads made of small updates.
Command-line enhancements xxhsum can now receive a full 64-bit seed through -s or --seed. Command-line parsing is more flexible: options may appear anywhere, even after filenames, while -- explicitly terminates option processing. When processing a list of files, read errors no longer prevent subsequent files from being processed. Windows support received a substantial update, notably for long paths, UNC paths and filenames containing components that require extended Win32 path handling.
Build and integration Runtime dispatch detection has been corrected for cross-compilation and non-x86 targets. make builds now isolate object files by configuration, avoiding accidental reuse across incompatible flag sets and allowing parallel test builds. The cmake integration moved from cmake_unofficial to build/cmake. Projects referring directly to the previous directory must update that path. Low-level integrations can now redirect XXH_memcpy(), XXH_memset() and XXH_memcmp(). A new XXH_NO_EXTERNC_GUARD macro is also available for projects that need to manage C++ linkage themselves.
Correctness and portability A strict-aliasing issue that could cause gcc to miscompile some unaligned reads has been fixed. This release also addresses combinations involving XXH_INLINE_ALL, namespaces and x86 runtime dispatch, system headers included from an extern "C" block, and MSVC link-time optimization with warnings enabled as errors. Portability improvements include compatibility with ARM builds using GCC versions older than 8, C++ compilation on Solaris and illumos, and improved installation metadata and paths on Windows and FreeBSD.
Detailed changelist
perf : added RISC-V Vector extension (RVV) implementation, by @zijianli1234, @BoBoDai and @camel-cdr
perf : added LoongArch LASX implementation and improved LSX, by @24bit-xjkp …
xxHash v0.8.3 is a maintenance update, featuring a bug fix and several quality of life improvements. Bug Fix - XXH3_128bits_withSecretandSeed() Corrects an edge case (#894) that could generate invalid results. Users of this function should upgrade. Thanks to @hltj for the report and fix.
Command-Line Improvements - Runtime Vector Extension on x86 xxhsum automatically detects and employs the best available vector extension (SSE, AVX, etc.) on x86/x64 cpus. Previously, this required an explicit build macro; it is now enabled by default. Maintainers can still control it manually, and can disable it with DISPATCH=0. - --filelist / --files-from Accepts file names from a text file or stdin, simplifying bulk hashing. Kudos to @Ian-Clowes for the idea and implementation. - Short GNU Format for XXH3 A new -H3 mode generates XXH3 64-bit hashes with a XXH3_ prefix, neatly distinguishing them from XXH64. The symlink xxh3sum defaults to this mode.
Portability - LoongArch SX SIMD Support Includes an optimized LoongArch SX implementation of xxh3 (courtesy of @lrzlin). - Extended Platform Coverage Validated builds for AIX OS and SPARC CPUs.
New Contributors
@scribam made their first contribution in #859
@klemensn made their first contribution in #880
@thestr4ng3r made their first contribution in #878
@cclauss made their first contribution in #895
@nathaniel-brough made their first contribution in #906
@crosdahl made their first contribution in #932 …
Frequently asked questions
Is xxhsum free?
Yes. xxhsum is free and open-source software released under the BSD-2-Clause license.
What is the latest version of xxhsum?
The latest version is 0.8.4, released on Sep 19, 2026.
Is it safe to download xxhsum?
The download button links to the official installer published on github.com, the same file Windows Package Manager installs. You can verify the downloaded file by comparing its SHA-256 checksum with 58e3dcb7063eb3829418453702556cdb2b52e7c9082215fcd4e9135fabbd4ed9.
Which Windows versions does xxhsum support?
xxhsum runs on Windows and is available for 64-bit (x64) systems.
How do I uninstall xxhsum?
Open Settings › Apps › Installed apps, find xxhsum and select Uninstall. From the command line, run winget uninstall --id=Cyan4973.xxhsum -e.
Is there a portable version of xxhsum?
Yes. xxhsum is available as a portable ZIP archive (xxhsum_win64_v0_8_4.zip, 64-bit (x64)) that runs without installation. Copy it to any folder or USB drive and run it from there.
Alternatives to xxhsum
Other Command Line Tools programs for Windows from different developers.
