ZIP, RAR, 7Z and TAR: which one to use and how to open them
, 4 min read
An archive is a container: many files packed into one, usually compressed. The formats differ mainly in who can open them.
The formats
| Format | Opens everywhere? | Notes |
|---|---|---|
| ZIP | Yes | Built into Windows, macOS, Android and iOS. The safe default when sending files to someone. |
| RAR | No | Proprietary. Creating RAR needs paid software, which is why recipients often get stuck. |
| 7Z | No | Free and compresses very well, but needs 7-Zip or similar installed. |
| TAR, TAR.GZ | On Linux and macOS | Common for source code and server backups. |
Opening what someone sent you
You do not need to install anything. Unzip Files, Extract RAR, Extract 7Z and Extract TAR all run in the browser. If you just want to see what is inside before extracting, ZIP and RAR Viewer lists the contents with sizes and dates.
Multi volume archives, the ones that arrive as part1, part2 and so on, are not supported and need desktop software.
Sending files to other people
Use ZIP. Create ZIP File bundles anything, and if the contents are sensitive, Password Protected ZIP adds AES-256 encryption. Choose AES rather than the older ZipCrypto option unless the recipient is using very old software, because ZipCrypto is weak and can be broken.
Holding a RAR you need to pass on? RAR to ZIP converts it so nobody has to install anything.
What compresses and what does not
Text, spreadsheets and code shrink a lot. Photos, videos, MP3s and PDFs full of images are already compressed and will barely change. Zipping a folder of JPEGs mostly just makes them easier to send as one file, which is still a good reason to do it.