7Z vs ZST — Differences, File Size & When to Use Each

7Z vs ZST

A detailed comparison of 7-Zip Archive and Zstandard Compressed — file size, quality, compatibility, and which format to choose for your workflow.

Convert 7Z → ZST Convert ZST → 7Z

7-Zip Archive

Archives & Compressed

7z uses the LZMA2 compression algorithm to achieve significantly better compression ratios than ZIP. It is open-source and supports strong AES-256 encryption.

About 7Z files

ZST

Zstandard Compressed

Archives & Compressed

Zstandard (Zstd) is a fast lossless compression algorithm developed by Yann Collet at Facebook. It provides compression ratios comparable to zlib while being 3-5x faster at both compression and decompression, making it ideal for real-time data processing.

About ZST files

Strengths Comparison

7Z 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.

ZST Strengths

Extremely fast decompression (~2 GB/s on modern CPU).
Scalable: very fast at level 1, near-xz ratios at level 22.
Dictionary support for small-payload efficiency.
Multi-threaded by default.
Standardized (RFC 8478), BSD-licensed reference.

Limitations

7Z 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.

ZST Limitations

Newer than gzip/bzip2 — some legacy tools still lack support.
At extreme compression levels, xz can still win on ratio.
Memory usage at high levels is significant.
Consumer archiving tools (Windows Explorer) lag behind.

Technical Specifications

Specification	7Z	ZST
MIME type	application/x-7z-compressed	application/zstd
Compression	LZMA, LZMA2, PPMd, Bzip2, DEFLATE	—
Max file size	16 EB (exabytes)	—
Encryption	AES-256 (content + filenames)	—
License	LGPL	—
Extension	—	.zst
Algorithm	—	LZ77 variant + entropy coding (FSE/Huffman)
Standard	—	RFC 8478 (2018)
Compression levels	—	1-22 (plus negative "fast" levels)

Typical File Sizes

7Z

Source code archive ~50% smaller than ZIP
Linux distro installer 2–10 GB
Virtual machine disk image 5–40 GB

ZST

Default level 3 on source code 28-35% of original
Level 22 ultra on source code 14-18% of original
Linux kernel (.tar.zst, level 19) ~130 MB

Ready to convert?

Convert between 7Z and ZST online, free, and without installing anything. Encrypted upload, automatic deletion after 60 minutes.

Convert 7Z to ZST Convert ZST to 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 is an open-source archive formato de the 7-Zip project. It uses the LZMA2 compressão algorithm which achieves significantly better compressão ratios than ZIP ou RAR, making it ideal para archiving large arquivos e 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.

7Z arquivos abrir com 7-Zip (free, Windows), PeaZip (cross-platform, grátis), Keka (macOS), e 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.

Use 7Z when máximo compressão is the priority, como software distribution e backups. usar ZIP when the recipient needs to abrir o arquivo sem installing extra software, since ZIP is natively suportado everywhere.