FixFile
File Format

7Z (.7z)

Open-source archive format from Igor Pavlov with the highest compression ratios available. Created by 7-Zip, free to use without any licensing restrictions.

Extension
.7z
MIME Type
application/x-7z-compressed

Last updated

Overview

7Z is an open-source archive format developed by Igor Pavlov as part of the 7-Zip software project, first released in 1999. It uses the LZMA (Lempel–Ziv–Markov chain Algorithm) compression method by default, which achieves significantly better compression ratios than ZIP's Deflate algorithm — typically 15–40% smaller for the same content.

Unlike RAR, 7Z is completely open-source under the GNU LGPL licence. The 7-Zip software is free for any use including commercial, and the 7Z format specification is publicly available. This openness has made 7Z a popular choice for software distribution and long-term archival.

Common Uses

  • Software distribution — many open-source projects distribute releases as .7z archives
  • Maximum compression archiving — when file size reduction is the primary goal
  • Cross-platform file packaging — 7Z is supported on Windows, macOS, and Linux without commercial software
  • System backup — 7-Zip's command-line interface integrates with backup scripts

Advantages

  • Best-in-class compression — LZMA algorithm achieves 15–40% better ratios than ZIP; up to 70% better for executable files
  • Completely free — no cost, no licensing, open-source format and software
  • AES-256 encryption — strong encryption available for protecting sensitive archives
  • Large file support — supports archive sizes up to 16 exabytes

Limitations

  • Slow compression — LZMA encoding is significantly slower than ZIP's Deflate; creating a 7Z archive takes 3–5× longer
  • No native OS support — requires 7-Zip or compatible software; not built into Windows, macOS, or Linux
  • Limited multi-part native support — multi-volume 7Z archives (7z.001, 7z.002...) are less commonly supported than RAR volumes
  • No recovery records — unlike RAR, 7Z has no built-in mechanism for recovering damaged archives

Supported Software

  • Windows: 7-Zip (official, free), WinRAR, PeaZip
  • macOS: Keka, The Unarchiver, 7zz (command-line)
  • Linux: p7zip, 7za (command-line), PeaZip, Ark
  • Online: FixFile.online ZIP Extractor (supports 7Z)

Tools for 7Z files