1 What Is a 7z File?
The basics.
A .7z file (also called "7-Zip archive") is a compressed archive format — like a ZIP or RAR file, but using a compression method called LZMA2 that often achieves smaller file sizes. It was created by the makers of the free 7-Zip software.
Windows and Mac don't natively open .7z files, but free tools handle them effortlessly.
2 Step-by-Step: Open Your 7z File
Choose your operating system.
Using 7-Zip (Free — Named After This Format!)
Download 7-Zip
Go to 7-zip.org and install the 64-bit version. It's free and takes 30 seconds.
Right-click the .7z file
Find your file in File Explorer, right-click it, and look for 7-Zip in the context menu.
Click "Extract Here" or "Extract to [folder]"
Your files will appear moments later. Enter a password if prompted.
WinZip also supports .7z files if you prefer a graphical interface with drag-and-drop.
Using The Unarchiver (Free)
Install The Unarchiver
Free from the Mac App Store. Search "The Unarchiver" and install.
Right-click → Open With → The Unarchiver
Find the .7z file in Finder, right-click, and choose The Unarchiver.
Done!
Files extract to the same folder. Enter password if prompted.
Keka (free from keka.io) is another great option for .7z files on Mac.
3 Why Would Someone Send a .7z Instead of .zip?
A fair question.
Better compression. 7z files are often 30–70% smaller than the equivalent ZIP, which matters for very large files. If someone is sending you multi-gigabyte data, .7z saves significant time and bandwidth.
Stronger encryption. The .7z format supports AES-256 encryption by default, and unlike ZIP files, it can also encrypt the file names — so nobody can even see what's inside without the password.
The trade-off is that .7z isn't as universally supported. That's why you're on this page! But with 7-Zip or The Unarchiver installed, you'll never have trouble with them again.