RAR Format Guide
Roshal Archive - High-Performance Compression Format
What is RAR Format?
RAR (Roshal Archive) is a proprietary compressed data format and conditionally-free archiver program. The version for Microsoft Windows is distributed as part of the multi-format archiver with graphical interface — WinRAR.
RAR files use sophisticated compression algorithms that can reduce file sizes by 10-15% more than ZIP format, making them ideal for long-term storage, backup solutions, and situations where bandwidth is limited. The format supports advanced features like error recovery, file spanning across multiple volumes, and strong encryption protection.
History
The format was developed by Russian programmer Eugene Roshal (hence the name: Roshal ARchiver). He wrote the archiver program for packing/unpacking RAR — initially for DOS, then for other operating systems.
Since 2004, the copyright for RAR and WinRAR belongs to Eugene's older brother — Alexander. As Eugene Roshal explained:
"I'll immediately answer possible questions about the copyright change: I simply don't have time to deal with both development and issues related to copyright protection. I continue to work on development as before, so for RAR users nothing changes in this regard."
📅 Key Milestones
- 1993: First RAR version released for DOS
- 1995: WinRAR for Windows 95 introduced
- 2004: Copyright transferred to Alexander Roshal
- 2013: RAR5 format introduced with enhanced features
- 2011: RAR v3 support added to "The Unarchiver" free toolkit
Main Features
RAR provides comprehensive archiving capabilities with advanced features that set it apart from other compression formats:
🗜️ Superior Compression
RAR consistently achieves better compression ratios than most other archive formats, thanks to its advanced compression algorithms and optimized data processing.
📀 Multi-Volume Archives
Creation and extraction of multi-volume archives consisting of several parts, useful for recording archives on small-capacity media (optical discs, flash drives, etc.).
🔧 Error Recovery
Additional recovery data can be added to archives, allowing restoration of physically damaged archives. Special .rev files can restore any damaged or missing volume in multi-volume archives.
⚡ Self-Extracting Archives
Creation of self-extracting (SFX) archives that can be run as regular executable EXE files to extract contents without additional software.
🧱 Solid Compression
Creation of "solid" archives where files are treated as a single continuous data stream, achieving significantly higher compression ratios for large collections of similar files.
🔒 Advanced Encryption
Password protection using AES encryption, including encryption of file names and service information, making it impossible to view archive contents without the correct password.
✅ File Integrity
RAR5 archives include BLAKE2 hash sums for virtually guaranteed accurate file identification, unlike CRC32 checksums which can be easily forged.
🚀 Fast Opening
RAR5 archives include service information that speeds up archive opening (listing contents), especially noticeable for large archives with many files.
📝 Additional Features
- Archive comments - Add descriptive text to archives
- NTFS permissions - Store and restore file access rights
- Virtually unlimited - No practical limits on number of files or their size
- PPMd algorithm - RAR 4.x supported PPMd compression for text data (high compression but slow processing)
- Unicode support - Full support for international file names
UnRAR
The source code of the UnRAR extractor has been released under a license that allows free distribution and modification, provided that it is not used to write a compatible packer. The compression method remains "closed" for PC users but is open for ZX Spectrum (RAR v2 only).
🔓 Open Source Extraction
UnRAR source code is freely available, allowing developers to integrate RAR extraction capabilities into their applications while preventing creation of competing RAR creators.
🌐 Multi-Platform Support
Extraction programs exist for multiple platforms: Windows, Linux, FreeBSD, macOS, Android. Third-party tools like 7-Zip also provide RAR extraction capabilities.
🕹️ Retro Computing
Interestingly, there exists a version of RAR that works on ZX Spectrum computers with Z80 processors (ZXRAR), demonstrating the format's adaptability.
Technical Specifications
| Specification | Details | Rating |
|---|---|---|
| File Extension | .rar, .rev (recovery volumes) | Standard |
| Compression Algorithm | LZMA, PPMd, BWT | Excellent |
| Maximum File Size | 8 exabytes (8,000,000 TB) | Unlimited |
| Compression Ratio | 10-15% better than ZIP | Superior |
| Encryption | AES-256, file name encryption | Strong |
| Platform Support | Windows, Mac, Linux (with software) | Good |
| Creation Software | WinRAR (proprietary) | Limited |
| Extraction Software | Multiple free options available | Widely Available |
Pros and Cons
✅ Advantages
- Superior compression ratios - Saves significant storage space
- Error recovery capabilities - Built-in repair mechanisms
- Strong encryption - AES-256 with filename protection
- Volume spanning - Split large archives across multiple files
- Advanced features - Comments, timestamps, and metadata preservation
- Password protection - Secure file access control
- Solid compression - Treats multiple files as one data stream
❌ Disadvantages
- Proprietary format - Controlled by single company
- Creation requires paid software - WinRAR license needed
- Slower compression - Higher CPU usage for better ratios
- Limited native support - Requires additional software on most systems
- Licensing restrictions - Commercial use may require license
- Platform dependency - Best supported on Windows
When to Use RAR Format
🎯 Ideal Use Cases
- Long-term archival storage - Maximum compression saves storage costs over time
- Backup solutions - Error recovery and solid compression for reliable backups
- Bandwidth-limited transfers - Smaller files mean faster uploads and downloads
- Large media collections - Compress photo, video, and document libraries efficiently
- Secure file storage - When encryption and password protection are required
- Distribution of large software - Common in software and game distribution
🚫 Avoid RAR When
- Universal compatibility needed - Recipients may not have RAR software
- Quick file sharing - ZIP is faster and more widely supported
- Web-based applications - Most platforms don't support RAR natively
- Mobile device access - Limited RAR support on mobile platforms
- Real-time compression - RAR's compression is slower than alternatives
Software and Tools
Creating RAR Files
- WinRAR - Official paid software (Windows/Mac/Linux)
- RAR for Linux - Command-line version
- Online converters - Web-based RAR creation tools
Extracting RAR Files
- WinRAR - Full-featured official client
- 7-Zip - Free alternative with RAR support
- WinZip - Commercial archive manager
- PeaZip - Free open-source archiver
- The Unarchiver - Free Mac utility
RAR Conversion Options
Need to convert your RAR files to other formats? Our online converter supports various RAR conversions: