Software & Apps File Types What Is an ARJ File? How to Open, Edit, & Convert ARJ Files By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated January 23, 2020 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the ARJ file extension is an ARJ Compressed file. Like most archive file types, they're used to store and compress multiple files and folders into one easily manageable file. Lifewire / Julie Bang ARJ files are useful if you're backing up lots of files or sharing several items with someone. Instead of losing track of all the files and folders or having to share each file specifically, you can package all of them into one ARJ file to treat the entire collection as if it were a single file. How to Open an ARJ File ARJ files can be opened with any popular compression/decompression program. I like 7-Zip and PeaZip, but there are several free zip/unzip tools to choose from, including the official ARJ program. If you're on a Mac, try The Unarchiver or Incredible Bee's Archiver. Regardless of the one you choose, any of these types of programs will decompress (extract) the contents of an ARJ file and some may also have the ability to create ARJ compressed files. The RAR app from RARLAB is an option for opening ARJ files on an Android device. You could also use Notepad or another text editor to open the ARJ file. Many files are text-only files, meaning no matter the file extension, a text editor may be able to properly display the file's contents. This isn't true for ARJ Compressed files but your ARJ file might actually be in a totally different, obscure format that's really just a text document. If you find that an application on your PC tries to open the ARJ file but it's the wrong application or you'd rather have another installed program open ARJ files, see our How to Change the Default Program for a Specific File Extension guide for making that change in Windows. How to Convert an ARJ File If you're wanting to convert an ARJ file to another archive format, the best way to do that would be to go ahead and extract all of the contents held in the ARJ file and then compress them to a new format using a file compressor from the list mentioned above. In other words, instead of looking for an ARJ to ZIP or RAR converter (or whatever format you want to convert the ARJ file to), it'd be easier and probably quicker to open the archive to detach all of its data. Then, just re-make an archive but choose the format you want, like ZIP, RAR, 7Z, etc. There are, however, online ARJ file converters, but since they make you upload the archive online first, they're not very useful if your archive is really large. If you have a small one, you can try FileZigZag. Upload the ARJ file to that website and you'll be given the option to convert it to a number of other formats like 7Z, BZ2, GZ/TGZ, TAR, ZIP, etc. You might try the online ARJ converter at Convertio if FileZigZag doesn't do what you want. Still Can't Open Your File? Files that don't open with the ARJ openers above are most likely not ARJ files. The reason you're mistaking your file for an ARJ archive might be if the file extension looks like ".ARJ" but is really just a letter or two off. For example, ARF, ARD, and ARY files share the same first two file extension letters, and so do ARJ files, but none of these formats are related and, therefore, won't open with the same programs.