About 7Z Files
7-Zip Archive
7z uses the LZMA2 compression algorithm to achieve significantly better compression ratios than ZIP. It is open-source and supports strong AES-256 encryption.
Family
Archives & Compressed
Extension
.7z
MIME Type
application/x-7z-compressed
Can Use As
HOW 7Z
CAME TO BE.
7z is the open-source archive format created by Russian programmer Igor Pavlov in 1999, shipped as part of the 7-Zip utility. The format's headline feature is LZMA compression — a dictionary-based algorithm that routinely outperforms ZIP and RAR by 20–50% on typical files. Its open license and technical superiority made it the archival format of choice for Linux distributions, software installers, and anyone optimizing for size over compatibility.
The 7-Zip utility itself became a Windows staple — free, open source, no nag screen, no bundled adware — and the Linux port (p7zip) is standard in every distribution. The format is licensed under the permissive LGPL and has no royalty or usage restrictions.
CURIOSITIES &
TRIVIA.
LZMA2 (7z's default codec) was later adopted by the xz utility — the compression ratio is legendary.
7z archives can hit 10× better compression than ZIP on text-heavy content.
7-Zip is one of the most-downloaded Windows utilities ever — hundreds of millions of installs.
The format supports AES-256 encryption on filenames AND contents — a feature ZIP still lacks in practice.
7z's author, Igor Pavlov, has maintained the project almost single-handedly since 1999.
STRENGTHS &
LIMITATIONS.
Strengths
- Outstanding compression ratio — typically 20–50% smaller than ZIP, 10–30% smaller than RAR.
- Completely free and open source.
- AES-256 encryption of both content and filenames.
- Supports enormous archives (16 exabytes).
- Multi-threaded compression on modern CPUs.
Limitations
- Not natively supported on Windows before Windows 11 23H2 or macOS — requires a separate tool.
- Slower compression than ZIP (though decompression is fast).
- No built-in recovery records like RAR.
- Less ubiquitous in email and casual sharing than ZIP.
Typical Sizes & Weights
Source code archive
~50% smaller than ZIP
Linux distro installer
2–10 GB
Virtual machine disk image
5–40 GB
Technical Specifications
- MIME type
- application/x-7z-compressed
- Compression
- LZMA, LZMA2, PPMd, Bzip2, DEFLATE
- Max file size
- 16 EB (exabytes)
- Encryption
- AES-256 (content + filenames)
- License
- LGPL
CONVERT FROM
7Z
Common Use Cases
Maximum compression, large file archives, encrypted storage.
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Frequently Asked Questions about 7Z
Frequently Asked Questions
7Z is an open-source archive format from the 7-Zip project. It uses the LZMA2 compression algorithm which achieves significantly better compression ratios than ZIP or RAR, making it ideal for archiving large files and datasets.
7Z files open with 7-Zip (free, Windows), PeaZip (cross-platform, free), Keka (macOS), and The Unarchiver (macOS). Windows does not natively support 7Z, so third-party software is required.
Use 7Z when maximum compression is the priority, such as software distribution and backups. Use ZIP when the recipient needs to open the file without installing extra software, since ZIP is natively supported everywhere.