7-Zip is a file archiver program that claims to compress files into smaller size compared to other programs such as WinRAR and WinZip. The program can pack and unpack various formats such as ZIP, GZIP, BZIP2, TAR, and of course, its own format, 7z. The 7z format itself is actually a container that supports few compression method such as LZMA, Deflate and BZIP2, with LZMA as default.