7-Zip is open source software. Most of the source code is under the GNU LGPL 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.

WinRAR is a powerful archive manager. It can backup your data and reduce the size of email attachments, decompress RAR, ZIP and other files downloaded from Inte

ZArchive is an application to create a single compressed file archive that contains many files. It is compiled using zlibar with FreePascal. Zlibar is distributed with the same modified LGPL as the LCL.