A 7Z file is a compressed archive created by various file compression utilities, most notably, Igor Pavlov's 7-Zip. It uses open-source LZMA compression, which has a high compression ratio and can include strong AES-256 (256-bit) encryption. 7Z files may contain multiple directories or files compressed to save space for storage or transportation purposes.

While 7z compression uses the LZMA method by default, the 7z format also supports the PPMD, BCJ, BCJ2, BZip2, and Deflate compression methods. The file type also supports Unicode file names, archive header compression, and file sizes up to 16,000,000,000 GB.