7-Zip is a free open-source file archiver, extractor and manager which supports most popular compression formats.
The utility is remarkable for the high compression ratio of its own archive format, .7z. The 7z archives can be considerably smaller than ZIP and RAR files, despite the fact that the compression process may take longer to compress and decompress. The list of compression formats supported by 7-Zip that can be packed and unpacked is not so impressive and includes 7z, ZIP, GZIP, BZIP2 and TAR, the number of supported extraction formats is quite extensive and includes ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z.
A nice feature in 7-Zip is its file splitting option which allows you to divide one large file into a few smaller ones. It can be useful in case it is necessary to send a large file via e-mail or upload it on a website with certain file size limits.
Apart from that, 7-Zip can encrypt archive files using AES-256 algorithm which is capable of using cryptographic keys of up to 256 bits and is considered one of the top ciphers.
7-Zip doesn't eat up system resources and can be easily switched to background mode. It's interface is intuitive, however, some users believe it is quite plain and primitive.
Apparently, 7-Zip is not as popular as WinRar or WinZIP and doesn't have a whole lot of features to mark it out from file archivers of its kind. Still, it offers all the necessary options needed in an archive manager and it's performance is just great.