Free online CAB to 7Z converter

A CAB file may need conversion when a storage, backup, or sharing workflow accepts 7Z but not Microsoft Cabinet archives. Repackaging it as 7Z can also add password protection or reduce size, although the original CAB may still be required by an installer or Windows servicing tool.

What the CAB format is

CAB, short for Microsoft Cabinet, is an archive format used mainly for Windows drivers, updates, system components, and application installers. Microsoft utilities such as makecab, Visual Studio deployment systems, and Windows installation components can create CAB files. A cabinet can contain multiple files, use MSZIP, LZX, or Quantum compression, and form part of a multi-cabinet set.

A CAB can be an installation component rather than a general-purpose archive. Converting it copies the contained files into a different container, but does not preserve the original installer behavior, cabinet-set relationships, servicing metadata, digital signatures, or required filename.

What the 7Z format is

7Z is a general-purpose archive format created for the 7-Zip project. It commonly uses LZMA or LZMA2 compression, supports Unicode filenames, solid archives, large files, and AES-256 encryption. With encrypted headers enabled, the archive also hides filenames and folder names.

7Z is suitable for storage, transfer, backups, and password-protected archives that will be opened with 7-Zip, PeaZip, compatible command-line tools, or other software with 7Z support. Windows Update and CAB-based installers normally do not accept a 7Z file as a replacement for their original CAB input.

How to convert CAB to 7Z with 7-Zip

1. Install 7-Zip from its official desktop distribution and open its File Manager, or use the 7-Zip context-menu commands in Windows Explorer.
2. Select the .cab file and choose 7-Zip → Extract to "folder\\". Extracting first is necessary because 7-Zip creates a new archive from extracted files; it does not change a CAB container directly into 7Z.
3. Select the extracted folder or its contents and choose 7-Zip → Add to archive....
4. Set Archive format to 7z. Select LZMA2 for a typical balance of compression and speed.
5. Enable Solid Block when the archive will usually be handled as one unit. Solid compression can reduce the size of similar files, but extracting or updating one file can require more processing.
6. Enter a password if required. Enable Encrypt file names to hide the archive's filenames and directory structure, then select OK.

To perform the same operation from a command prompt, use:

7z x package.cab -oextracted
7z a -t7z package.7z ./extracted/*
7z t package.7z

The first command extracts the CAB, the second creates the 7Z archive, and 7z t tests the resulting archive. Keep the original CAB until the new archive has been opened and checked. On macOS and Linux, the executable may be named 7zz or 7z, depending on the installed package; shell wildcards can omit hidden files, so use a graphical file manager or an appropriate recursive command when necessary.

Other local software

PeaZip can read CAB archives and create 7Z archives on supported Windows and Linux installations. The conversion principle is the same: extract the CAB, create a new archive from the extracted files, select 7Z, and configure compression or encryption.

Convert without installing software

You can convert the file on 101convert.com for free without installing software: select the CAB file, choose 7Z as the output format, start the conversion, and download the result. Do not upload confidential files, private keys, licensed software, or data restricted by an organizational policy to a web converter.

Quality and compatibility limitations

The files are normally copied without changing their byte contents, but the archive container, compression method, paths, timestamps, attributes, and other metadata can differ. CAB files that already contain compressed data, such as JPEG images, MP4 video, ZIP files, or some installer payloads, may show little or no size reduction in 7Z. Compression level, dictionary size, solid mode, and available memory also affect the result.

Compare the file count, directory paths, and checksums after conversion when integrity matters. A successful archive test confirms that the 7Z structure is readable; it does not prove that a Windows installer, update tool, driver package, or vendor application will accept the converted archive. Retain the original CAB whenever it may be needed for installation, servicing, signature validation, or a later repair operation.