Convert OBB to RAR

A sharing or backup service may require RAR instead of accepting a raw Android expansion file. Creating a RAR archive packages the OBB without changing its contents; extracting it restores the original file.

What the OBB format is

OBB is the filename extension used for Android application expansion files. Large games and other apps may store graphics, audio, maps, video, and other resources outside the APK, commonly under Android/obb/<package-name>.

Typical names include main.1234.com.example.game.obb and patch.1234.com.example.game.obb. The associated app checks the package name, version, filename, and expected location. An OBB is not a general-purpose archive that Android can load while it is inside another archive.

OBB expansion files are an older distribution model; newer Google Play apps may use Play Asset Delivery instead. Some OBB files are produced with Android's JOBB tool and can contain encrypted or otherwise protected data. Packaging such a file in RAR does not decrypt, edit, or convert that data.

What the RAR format is

RAR is a compressed archive format that can contain one or more files. It supports lossless compression, password encryption, recovery records, comments, and split volumes such as game.part1.rar and game.part2.rar.

RAR is useful when a recipient or service specifically requires it, or when several OBB files, APK files, and related data need to be transferred as one package. It is not an Android expansion format: the OBB must be extracted before the app can use it.

How to create a RAR from an OBB

Using WinRAR on Windows

1. Install WinRAR from the official RARLAB website.
2. Copy the OBB to a local folder and close the associated game or app before handling the file.
3. Right-click the file and select WinRAR → Add to archive....
4. Set Archive format to RAR, choose a compression method, and enter a destination such as game-data.rar.
5. Select OK. WinRAR creates a RAR archive containing the unchanged OBB.

To package several files, select them together before choosing Add to archive.... To split the result, enter a value such as 4G in Split to volumes, size. Keep every volume in one folder; the recipient opens the first volume, normally .part1.rar.

Using a command line

With the RAR command-line executable installed, run this from the directory containing the file:

rar a game-data.rar main.1234.com.example.game.obb

To archive all files in an expansion-data directory, specify the directory contents explicitly, for example:

rar a game-data.rar Android\obb\com.example.game\*

The command-line RAR tools are distributed by RARLAB. 7-Zip can extract RAR archives but does not create them. On Android, RAR by RARLAB can create a RAR archive, although a desktop system is preferable for very large files and for reliable transfers.

Online services and alternatives

Online conversion is usually the wrong tool for this operation. Services such as CloudConvert or Convertio may not accept OBB input or create RAR output, and uploading a large game-data file exposes proprietary content and may hit size limits. Use an online service only if it explicitly lists both OBB input and RAR output, states that it creates an archive rather than merely renaming the extension, and meets the file's privacy requirements.

Do not rename file.obb to file.rar; changing the extension does not create a RAR archive. ZIP or 7z can be suitable alternatives when the recipient accepts them, but they are different archive formats and may require different software.

Compatibility and data limits

RAR compression is lossless, so extraction produces a byte-for-byte copy of the OBB. OBB resources often contain already-compressed audio, images, video, or packaged data, so the RAR may be only slightly smaller. Choose Store when creation speed matters more than compression.

To restore the expansion file, extract it and place it at Android/obb/<package-name>/ using its original filename. The installed APK must expect the same package identifier and compatible expansion-file version. Android versions may restrict access to this directory, and some apps download, authenticate, or verify their expansion data through their own installer; a correctly extracted OBB therefore may still not function when copied manually.