What Is WinRAR?

by Matthew Skiffington

WinRAR is a file utility used to compress redundant strings of code, thereby reducing the file size. Developed by RARLabs, it has a free-to-use trial version and is exceptionally popular among frequent users of file compression utilities. It provides a good alternative to WinZip, and allows users to choose between lossless and lossy compression methods. It uses highly advanced algorithms and has been in development since 1995.


WinRAR, as with any file compression utility, attempts to reduce the size of a file by reducing the amount of redundant information contained within it. For example, if the file contains a string of characters such as "xor pushpushpush movmov xor", WinRAR would compress the string as "xor [3]push [2]mov xor." Compression such as this is known as lossless compression. Another type of file compression is lossy compression, which employs techniques such as rounding. For example, if a file reads "2.98323425", rounding would simply display it as 3. Lossy compression cannot be reversed, and is only employed on file types in which file integrity is not critical. For example, in photos, most of the information is beyond human perception. Reducing the clarity of the picture by 25 percent is still out of the spectrum of human detection.


There are many benefits to using WinRAR over a basic, OS-provided compression utility such as WinZip. WinRAR uses highly advanced compression algorithms, can be adjusted to use lossless or lossy encryption methods, and also has the ability to break up a compressed file into subfiles. Subfiles are smaller segments of the original file which can be reconstituted by WinRAR upon decompression. Subfiles allow for greater convenience in file transmission and can be used to circumvent the file size limits imposed by many email services. WinRAR also has the ability to create self-extracting archives. Self-extracting archives can be extracted without requiring the recipient to have WinRAR installed, so long as the host computer can meet system requirements.


WinRAR cannot reduce the size of every file type. In particular, file types such as photos or music do not include many strings of redundant code and are therefore hard to compress using lossless algorithms. However, this does not mean a photo cannot be compressed---using lossy algorithms such as rounding, even photos can be compressed at a slight loss of quality.


WinRAR has been in development since 1995. Primary developed by Eugene Roshal under the guise of RARLabs, it has been one of the main holders of file compression utility market share. Since 2002, it has more recorded downloads and purchases than even its primary competitor, 7Zip. In October 2007, RARLabs released WinRAR Unplugged, a portable version of WinRAR that has no installation requirements nor dependencies on the extraction computer.


As WinRAR offers the end user the ability to choose among the various compression methods, a user may choose to apply lossy encryption on, for example, an EXE file. This can result in the EXE malfunctioning, or simply not functioning at all. Likewise, using lossless compression on a file that cannot be reduced with lossless compression will have a negligible effect on the file. Users must be cautious and educate themselves on the compression techniques and learn to use the most effective technique for the file they are attempting to compress.

About the Author

Matthew Skiffington is a teacher of special needs preschoolers in Newport News, Va. He graduated from Old Dominion University with a Master of Science in early childhood special education in 1997. Skiffington has written professionally for various websites since 2009, specializing in health, science and gaming-related topics.