RAR File Format (.rar)
A RAR file holds data compressed with RARLAB's proprietary algorithm, which since RAR5 in 2013 has combined LZSS-style matching with a PPMd model and can span a single archive across multiple numbered volumes.
RAR at a glance#
| Full name | Roshal Archive |
|---|---|
| File extension | .rar |
| Category | Archives |
| Developer | Eugene Roshal |
| First released | 1993 |
| MIME types | application/vnd.rarapplication/x-rar-compressed |
| Compression | Lossless |
| FileFlip support | FileFlip reads this format but does not write it |
What a .rar file can hold#
These are the things a RAR file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.
| Encryption | Yes |
|---|
Strengths and limitations of RAR#
What RAR does well
- Recovery records can reconstruct part of a damaged archive without needing the original file back
- Native multi-volume support splits an archive into numbered parts, useful for size-capped transfers
- PPMd compression mode often beats DEFLATE on text and mixed content
- AES-256 encryption in RAR5 can also hide file names and the archive's internal structure
Where RAR falls short
- The RAR compressor is proprietary and commercial, sold as WinRAR or the rar command-line tool, so nothing free can create a RAR archive, only extract one
- Not opened natively by Windows or macOS without installing extra software
- No open specification for the compression algorithm; the published unrar source is licensed only for decompression, not for building a compatible writer
Use RAR when an archive needs to be split across multiple size-capped volumes or carry a recovery record that can survive some file damage.
Convert RAR to ZIP or 7z when the archive needs to be rebuilt or edited, since nothing free can write a new RAR file, only read one.
How to open a .rar file#
A .rar file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts RAR into a format your machine already opens, and it does it in the browser tab rather than on a server.
| Platform | Programs that open it |
|---|---|
| Windows | WinRAR, 7-Zip, PeaZip |
| macOS | The Unarchiver, Keka |
| Linux | unrar, Ark |
| iOS | RAR |
| Android | RAR, ZArchiver |
| Web | FileFlip |
RAR questions people ask#
Why can I only extract RAR files but not create them for free?
RAR is Eugene Roshal's proprietary format, and RARLAB only licenses the compressor, sold as WinRAR or the rar command-line tool, while distributing the unrar decompression source freely under a license that explicitly forbids using it to build a compatible archiver. That's why free tools like 7-Zip and The Unarchiver can open RAR files but none of them can write one.
What is a RAR recovery record?
A recovery record is optional redundant data a RAR archive can store alongside the compressed files, which lets tools reconstruct part of the archive if it gets corrupted or truncated later. It has to be added when the archive is created; a RAR without one can't be repaired after the fact.
Why is a RAR split into .part1.rar, .part2.rar files?
That's RAR's native multi-volume support, which splits one archive across several numbered files so it fits somewhere with a size limit, like an email attachment cap. All the parts have to be present to extract the contents.
What's the difference between RAR4 and RAR5?
RAR5, introduced in 2013, raised the maximum dictionary size to 1 GB, switched to 256-bit AES encryption and BLAKE2 hashing, added UTF-8 filename support, and improved multicore decompression speed over the older RAR4 format. Current WinRAR still reads and writes both.
Is WinRAR the only way to create a RAR file?
Effectively yes: WinRAR and RARLAB's command-line rar tool are the only compressors licensed to write the format, and both are commercial software sold after a 40-day trial. No free or open-source tool can produce a genuine RAR archive, which is why every other archive manager only extracts RAR files rather than creating them.
Converting RAR files#
Convert RAR to another format
FileFlip does not write .rar files, so nothing on the site converts into this format. It works as a source only.
Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.