Archives are the quiet workhorses of file sharing. You use them to bundle a folder of photos, send a project to a colleague or download software, and most of the time you never think about the format. Then someone sends a .rar or .7z file, your computer has no idea what to do with it, and suddenly the format matters. This guide explains the common archive types and when converting one into another makes life easier.
What an archive actually does
An archive does two separate jobs. It packs many files and folders into a single file, keeping the folder structure, and it usually compresses the contents to save space. Some formats do both in one step; others, like TAR, only pack and leave compression to a second tool. How much space you save depends on the content. Text, spreadsheets and source code shrink well. JPG photos, MP4 videos and MP3 audio are already compressed, so zipping them mostly just bundles them without making them much smaller.
ZIP: the one everyone can open
ZIP is the most widely supported archive format. Windows and macOS can open and create ZIP files without extra software, and so can most phones, email services and cloud storage tools. Many other file types, including DOCX, XLSX and EPUB, are ZIP archives internally. Its compression is usually not the strongest available, and the encryption in older ZIP tools is weak, but its compatibility is unmatched. When you send files to someone whose setup you don't know, ZIP is the safe choice.
RAR: common in downloads, awkward to create
RAR is a proprietary format created for the WinRAR program. It compresses well and has useful features such as recovery records, which can help repair a damaged archive, and splitting into multiple volumes. You still see it often in downloads and older collections. The catch is that creating RAR files requires WinRAR or a licensed tool, and opening them may need extra software depending on the system. If you receive a RAR and want to pass the files on, repacking them as ZIP saves the next person the trouble.
7Z: strong compression, open format
7Z is the native format of 7-Zip, a free and open-source archiver. Its default compression methods are typically more efficient than classic ZIP, which helps with large text-heavy folders, backups and software. It also supports AES-256 encryption, including encrypted file names. Support outside dedicated archive tools is less universal, so a 7Z may not open by double-clicking on every computer or phone. It is a good choice for your own storage or for people who already have 7-Zip or a similar tool.
TAR, TAR.GZ and friends: the Unix family
TAR comes from Unix systems and only packs files together, keeping permissions and timestamps. It is normally combined with a compressor, giving names like .tar.gz or .tgz (gzip), .tar.bz2 and .tar.xz. These are standard for Linux software, server backups and source code releases. macOS and Linux handle them out of the box, and recent Windows versions include a tar command, though many Windows users still reach for a separate archiver.
Which format to use
- Sending files to anyone, especially by email or chat: ZIP.
- Your own backups where smaller size matters: 7Z.
- Linux, servers and code releases: TAR.GZ or TAR.XZ.
- Receiving RAR or 7Z that you need to forward: convert to ZIP first.
- Sensitive files: use an archiver with AES encryption and share the password through a different channel.
Converting archives safely
- Extract and check the contents before repacking, especially for files from unknown sources.
- Password-protected archives have to be unlocked with the password before any conversion.
- Multi-part archives (part1, part2 and so on) need every part present.
- Keep the original until you have opened the new archive successfully.
- Avoid uploading archives with confidential documents to any online service whose file handling you have not checked.
For quick one-off conversions in the browser, CleverUtils is a free converter made in Kyiv, Ukraine, with 200+ converters, including https://cleverutils.com/rar-to-zip. It needs no account, adds no watermarks, and deletes uploaded files after 2 hours.