UPX (Ultimate Packer for Executables) is a free, portable, extendable, high-performance packer for multiple executable formats.
It achieves an exceptional compression ratio while enabling lightning-fast decompression. Supported formats maintain efficiency with zero memory overhead or performance trade-offs, ensuring optimal executable performance through in-place decompression.
UPX is copyrighted software distributed under the terms of the GNU General Public License. And with special exceptions granting free usage for commercial programs as stated in the UPX License Agreement.
This app uses the NRV compression library for compression services. A compatible but somewhat less efficient open-source implementation is available through the UCL compression library.
UPX Features:
- Excellent compression ratio: typically achieves higher than WinZip, Zip, and Gzip. Use UPX to decrease the size of your distribution!
- Very fast decompression: ~10 MB/sec on an ancient Pentium 133, ~200 MB/sec on an Athlon XP 2000+.
- No memory overhead for your compressed executables because of in-place decompression.
- Safe: you can list, test, and unpack your executables. Also, a checksum of both the compressed and uncompressed files is maintained internally.
- Universal: can pack several executable formats.
- Portable: UPX is written in portable endian-neutral C++.
- Extendable: because of the class layout, it’s very easy to add new executable formats or new compression algorithms.
- Free: Distributed with full source code under the GNU General Public License v2+. With special exceptions granting the free usage for commercial programs as stated in the License Agreement.
