RAR Format Guide

Available Conversions

About RAR Format

RAR (Roshal Archive) is a proprietary archive file format that supports data compression, error recovery, and file spanning. Developed by Russian software engineer Eugene Roshal, RAR has become one of the most popular compression formats worldwide due to its superior compression ratios and advanced features. The format is particularly favored for archiving large files, creating backups, and distributing software where file size reduction is critical.

History of RAR

RAR was created by Eugene Roshal in 1993, with the first DOS version released that same year. The name "RAR" stands for "Roshal Archive" after its creator. WinRAR, the graphical Windows version, was introduced in 1995 and quickly became the standard RAR compression tool. In 2004, the copyright was transferred to Eugene's brother, Alexander Roshal, who continues to maintain and develop the software. The RAR5 format, introduced in 2013, brought significant improvements including better compression algorithms (LZMA2), stronger encryption (AES-256), and improved error detection using BLAKE2 hash functions instead of CRC32. While the compression algorithm remains proprietary, the extraction code (UnRAR) has been made available under a restricted license, allowing free distribution and use of extraction tools.

Key Features and Uses

RAR archives offer several advanced features that distinguish them from other compression formats. Solid compression treats multiple files as a continuous data stream, achieving significantly better compression ratios for collections of similar files. Multi-volume archives allow splitting large archives across multiple files, useful for storage on media with size limitations. Error recovery records can be added to archives, enabling repair of physically damaged files. RAR supports strong AES-256 encryption with the ability to encrypt file names, making archive contents invisible without the correct password. The format also supports archive comments, NTFS file permissions, Unicode filenames, and virtually unlimited file sizes (up to 8 exabytes). RAR5 archives include service information that speeds up archive opening, and BLAKE2 hash sums provide better file integrity verification than traditional CRC checksums.

Common Applications

RAR is widely used in scenarios where maximum compression is important: long-term archival storage, backup solutions, software and game distribution, and bandwidth-limited file transfers. The format's superior compression ratios (typically 10-15% better than ZIP) make it ideal for reducing storage costs and transmission times. RAR archives are common in file sharing communities, software distribution (particularly in gaming and professional software), and enterprise backup systems. The format is also popular for creating secure archives due to its strong encryption capabilities. While WinRAR (the official compression tool) is commercial software, numerous free extraction tools are available across all major platforms, including 7-Zip, PeaZip, and The Unarchiver, making RAR archives accessible despite the proprietary compression algorithm.

Advantages and Disadvantages