FormatDrop
Document Format

7Z

7-Zip Archive

7Z (7-Zip Archive) is an open-source archive format developed by Igor Pavlov for the 7-Zip software. It achieves the highest compression ratios of any mainstream archive format — typically 30–50% smaller than ZIP and 10–20% smaller than RAR for the same content. 7Z is free, open-source, and fully documented. It's the preferred format for software distribution, backups, and any use case where minimising archive size is the priority.

What is 7Z?

7Z uses the LZMA (Lempel-Ziv-Markov chain Algorithm) or LZMA2 compression algorithm — more computationally intensive than ZIP's Deflate but significantly more effective. The 7Z format supports solid compression (compressing multiple files as a single block for better ratios on similar files), AES-256 encryption with password protection (including encrypting filenames), multi-volume archives, multiple compression algorithms (LZMA, LZMA2, BZip2, PPMd, Delta), and self-extracting archives. The 7Z format specification is open and freely available — anyone can implement it.

7Z pros and cons

Advantages

  • Highest compression ratios of any mainstream format
  • Completely free and open-source (GNU LGPL licence)
  • AES-256 encryption with optional filename encryption
  • Supports multiple compression algorithms
  • Cross-platform: 7-Zip for Windows, p7zip for Linux/Mac
  • Self-extracting archive support
  • Can decompress many other formats (ZIP, RAR, TAR, GZ, etc.)

Limitations

  • Slower to compress than ZIP (LZMA is CPU-intensive)
  • Not natively supported on older operating systems
  • Less universal than ZIP for sharing with non-technical users
  • No built-in error recovery (unlike RAR)
  • Solid archives can cause slow random file access
  • High memory usage during compression with LZMA

When should you convert 7Z files?

Convert 7Z to ZIP when sharing with users who don't have 7-Zip installed — ZIP is built into all modern OS. Convert 7Z to TAR.GZ for Linux/Unix deployment. Extract and re-compress when converting between formats: 7-Zip handles both extraction and re-compression. Keep 7Z for your own storage and backup archives where maximum compression matters — the size savings are significant on large archives. Use 7Z for software distribution where the 7-Zip installer is small and easily installed.

All FormatDrop conversions run entirely in your browser — no file upload, no server processing. Your files stay on your device.

7Z FAQ

How do I open a 7Z file?
Windows: 7-Zip (free, 7-zip.org) opens 7Z natively — right-click → 7-Zip → Extract Here. Windows 11 23H2+ can open 7Z in File Explorer natively. macOS: The Unarchiver, Keka, or p7zip in Terminal (`7z x archive.7z`). Linux: `7z x archive.7z` or `p7zip -d archive.7z` (install via package manager: `apt install p7zip-full`). WinRAR also opens 7Z files.
Is 7Z better compression than ZIP?
Yes — typically 30–70% better compression than ZIP on mixed content, depending on file types. Text files and source code compress dramatically better with LZMA. Binary files, images, and already-compressed content see smaller gains. The trade-off is slower compression speed (LZMA is 3–5x slower than ZIP's Deflate) and higher memory usage.
How do I create a 7Z file?
7-Zip (Windows): right-click files or folders → 7-Zip → Add to archive → set archive format to 7Z. Command line: `7z a archive.7z files/`. macOS: `brew install p7zip` then `7z a archive.7z files/`. Linux: `7z a archive.7z files/` (after installing p7zip-full). The default compression level is 'Normal' — use 'Ultra' for maximum compression at the cost of more time.
Can 7Z files be password protected?
Yes — 7Z supports AES-256 encryption with password protection, including encrypting the file list (so the filenames inside are also hidden). In 7-Zip: Add to archive → set Encryption method to AES-256 → enter a password. Check 'Encrypt file names' for maximum privacy. Use a strong password — AES-256 encryption is effectively unbreakable with a good password.

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HEICWebPAVIFEPUBWebMOpusMP3WAVM4AFLACAACMP4AVIMKVMOVJPGPNGGIFSVGTIFFICOBMPEPSARWOGGWMVPPTXPagesPDFDOCXRAWHEVCH.264AIFFM4VWMA3GPDNGRTFPSDOGVTSFLVAIXLSXCSVZIPAPNGMIDIJPEG XLMPG/MPEGVOBM2TSAC3ALACDTSJP2HEIFAPECBZ3G2SRTDOCPPTXLSODTODSM3URARM4BAMRTXTMOBITARGZJSONXMLYAMLKEYMTSCR2NEFMXFTGACAFASSVTTDSFRMF4VWVASFRMVBORFRW2EAC-3TTA