7-Zip ~ File Archiver

7-Zip is a file archiver with a high compression ratio. 7-Zip is open source software. Most of the source code is under the GNU LGPL license. The AES code is under a BSD LICENSE. The unRAR code is under a mixed license: GNU LGPL + unRAR restrictions.

You can use 7-Zip on any computer, including a computer in a commercial organization. You don’t need to register or pay for 7-Zip. 7-Zip works in Windows 98/ME/NT/2000/XP. There is a port of the command line version to Linux/Unix.

The main features of 7-Zip

High compression ratio in new 7z format with LZMA compression
Supported formats:
- Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR
- Unpacking only: RAR, CAB, ISO, ARJ, LZH, CHM, Z, CPIO, RPM, DEB and NSIS
For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
Self-extracting capability for 7z format
Integration with Windows Shell
Powerful File Manager
Powerful command line version
Plugin for FAR Manager
Localizations for 63 languages

Compression ratio results are very dependent upon the data used for the tests. Usually, 7-Zip compresses to 7z format 30-70% better than to zip format. And 7-Zip compresses to zip format 2-10% better than most of other zip compatible programs.