What is RAR Archive?
Complete guide to the RAR file format
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What is RAR Archive?
RAR is a proprietary archive format known for its excellent compression ratio and multi-volume archive support. It was developed by Eugene Roshal and is primarily created using WinRAR software.
RAR archives typically achieve 10-15% better compression than ZIP and offer features like error recovery records, multi-volume splitting, and solid archives for maximum compression.
How RAR Works
RAR is a proprietary format whose compression engine combines an LZ-based sliding-window stage with a context-mixing predictor (PPMd) for suitable data.[3] Its solid archive mode treats grouped files as one continuous data stream so that redundancy across many small, similar files can be exploited, improving the ratio over per-file compression.[1] RAR can also embed Reed-Solomon recovery records that let a damaged archive be repaired without the original source.[2]
Versions and Licensing
The format was created by Eugene Roshal, whose first name and surname give RAR its name (Roshal ARchive).[3] The current RAR 5.0 format, introduced in 2013, raised the dictionary size, switched to 256-bit AES encryption, and changed the file structure, so older tools cannot read it.[2] While the decompression algorithm has historically been documented to allow third-party readers such as UnRAR, the compressor remains closed and creating RAR files requires licensed software like WinRAR.[1]
Technical Details
RAR vs Other Archive Formats
| Feature | RAR | ZIP | 7z |
|---|---|---|---|
| Compression ratio | High[2] | Moderate | Highest |
| Recovery record | Yes[2] | No | No |
| Multi-volume | Yes[1] | Yes | Yes |
| Open/proprietary | Proprietary[3] | Open | Open |
| Built-in OS support | No | Yes | No |
| Best for | Resilient archives | Universal sharing | Maximum compression |
RAR offers strong compression and unique recovery records, but it is proprietary, whereas ZIP is universally supported and 7z is open with the best ratios.
Pros and Cons
Advantages
RAR typically achieves 10-15% better compression than ZIP for most file types.
Recovery records allow repair of partially corrupted RAR archives.
Large archives can be split into multiple files of specified sizes.
RAR solid archives achieve even better compression by treating all files as one stream.
Disadvantages
RAR is proprietary - creating RAR files requires paid WinRAR software.
RAR is not natively supported by Windows or macOS without additional software.
RAR has less universal support than ZIP, especially on mobile devices.
WinRAR creation requires purchasing a license (though it works indefinitely in trial mode).
When to Use RAR Archive
Here are the most common situations where RAR Archive is the right choice:
Large Archive Distribution
RAR is commonly used for distributing large software and game files online.
Multi-Volume Archives
When splitting large backups or downloads across multiple parts, RAR is the standard.
Maximum Compression
When ZIP's compression is insufficient, RAR provides better ratios.
File Backup
RAR with error recovery records provides more robust backups than ZIP.
Convert RAR Archive Files
Need to convert your RAR files? Use our free online converter.
Try Archive Converter FreeFrequently Asked Questions about RAR Archive
How do I open RAR files?
Download 7-Zip (free) or WinRAR to open RAR files. 7-Zip is free and works excellently.
Is RAR better than ZIP?
RAR has better compression and error recovery but ZIP has wider native support. Choose based on your needs.
Can I create RAR files for free?
No, creating RAR files requires WinRAR (paid). Use 7Z format instead for free high-compression archiving.
What is the difference between RAR and RAR5?
RAR5 is the newer RAR format version with improved compression. WinRAR 5+ creates RAR5 by default.
Can Mac open RAR files?
macOS does not natively support RAR. Use The Unarchiver or Keka (free apps) to open RAR files on Mac.