7-Zip is free software with open source.
The most of the code is under the GNU LGPL license.
Some parts of the code are under the BSD 3-clause License. Also, there is unRAR license restriction for some parts of the code.
Please Read 7-Zip License information.
Anyone 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.
The main features of 7-Zip
High compression ratio in 7z format with LZMA and LZMA2 compression
Packing / unpacking: 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM
Unpacking only: AR, ARJ, CAB, CHM, CPIO, CramFS, DMG, EXT, FAT, GPT, HFS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RPM, SquashFS, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR and Z.
For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
Strong AES-256 encryption in 7z and ZIP formats
Self-extracting capability for 7z format
Integration with Windows Shell
Powerful File Manager
Powerful command line version
Plugin for FAR Manager
Localizations for 87 languages
7-Zip works in Windows 10 / 8 / 7 / Vista / XP / 2019 / 2016 / 2012 / 2008 / 2003 / 2000.
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 compressed to zip format 2-10% better than most of other zip compatible programs.
p7zip – the port of the command line version of 7-Zip to Linux/Posix.
On 7-Zip’s Sourceforge Page you can find a forum, bug reports, and feature request systems.