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

7Z vs CAB

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

Convert CAB → 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

CAB

Windows Cabinet

Archives & Compressed

CAB (Cabinet) is a Windows archive format used for software installers.

About CAB 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.

CAB Strengths

Multi-volume — designed for disk-spanning archives.
Multiple compression algorithms in one format.
Native Windows support for 30+ years.
Authenticode signing integrates with Windows security stack.
Microsoft-maintained tooling (MAKECAB, EXTRAC32, expand.exe).

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.

CAB Limitations

Windows-only ecosystem — limited Mac/Linux tooling.
Proprietary container with partial public documentation.
Overtaken by MSI (which uses CAB internally) for new installers.
Compression ratios lag modern formats (zstd, xz).

Technical Specifications

Specification	7Z	CAB
MIME type	application/x-7z-compressed	application/vnd.ms-cab-compressed
Compression	LZMA, LZMA2, PPMd, Bzip2, DEFLATE	MSZIP (DEFLATE), Quantum, LZX
Max file size	16 EB (exabytes)	—
Encryption	AES-256 (content + filenames)	—
License	LGPL	—
Extension	—	.cab
Max volume size	—	2 GB per file
Multi-volume	—	Yes (split archive spanning)

Typical File Sizes

7Z

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

CAB

Single driver package 100 KB - 20 MB
Windows Update patch 1-500 MB
Service pack archive 200 MB - 2 GB

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

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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.