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Archive format

CAB converter

A .cab file is a Microsoft Cabinet archive, the compression container Windows itself uses for installers, driver packages, and system updates. You usually meet one inside a setup program rather than as something people create by hand.

Private for supported formats — processed in your browser

Convert supported files

Runs on your device

Drop CAB files here

Batch files can each use a different output. Nothing uploads for local conversions.

Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.

Where CAB comes from

Microsoft introduced Cabinet — originally codenamed Diamond — in the mid-1990s for Windows 95 setup media, and it has carried Windows Update payloads, driver packages, and ActiveX distributions ever since. The specification is published, and open implementations exist through cabextract and libarchive.

How CAB works

  • Supports three compression schemes: MSZIP (DEFLATE), the stronger LZX, and the older Quantum.
  • A file's data can span folder boundaries and even continue into the next cabinet — a design built for floppy-disk sets.
  • Authenticode signatures can cover an entire cabinet, which is why Windows trusts signed driver .cab packages.
  • Design limits cap a cabinet at roughly 2 GB, reflecting its 1990s origins.

When to use CAB

  • Windows Update and servicing stack payloads.
  • Driver packages installed through INF files.
  • The internals of MSI installers.
  • Pulling individual files out of Windows setup media.

Strengths and limitations

Strengths

  • Authenticode signing makes packages verifiable end to end.
  • LZX compresses impressively for a 1990s-era codec.
  • Windows includes both makecab and expand, so no third-party tools are needed there.
  • Open documentation enabled cross-platform extractors.

Limitations

  • Windows-centric, with little reason to choose it for general archiving.
  • The ~2 GB ceiling rules out large modern payloads.
  • Far smaller tooling ecosystem than ZIP or 7z.

Compatibility

Windows opens .cab directly in File Explorer and ships command-line tools for creating and expanding cabinets. Linux and macOS extract them with cabextract or libarchive — the same library whose WebAssembly build lets this site unpack cabinets in the browser.

Convert CAB to another format