.zip

What is a .zip file?

ZIP is the universal archive format — bundles files with lossless compression, opens natively on every operating system.

Use caution
Type Archive
By Phil Katz / PKWARE
MIME application/zip

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What is it

You downloaded something from the internet. It arrived as a ZIP. This is the default because ZIP is the one archive format every operating system opens without installing anything — Windows, macOS, and Linux all handle it natively. Phil Katz created it in 1989, and it has outlived almost every technology from that era.

ZIP uses lossless compression, so nothing is lost or degraded — your files come out byte-for-byte identical to what went in. It supports password protection, though the older ZipCrypto encryption is weak enough to crack with free tools. If security matters, use AES-256 encryption (7-Zip creates AES-encrypted ZIPs). ZIP's compression ratio isn't the best — 7z and RAR squeeze harder — but compatibility is king.

Windows Explorer, macOS Finder, and every Linux file manager open ZIP files with a double-click. For creating ZIPs, the same built-in tools work. 7-Zip (free, Windows) gives you more control over compression levels and encryption. If you're sending files to someone and don't know what software they have, ZIP is the only polite choice.

Technical details
Full Name
ZIP Archive
MIME Type
application/zip
Developer
Phil Katz / PKWARE
Magic Bytes
50 4B 03 04
Safety
.zip requires caution. ZIP files from unknown sources may contain malware. Scan contents before extracting.
What opens it
Built-in OS support
FREE All
7-Zip
FREE Windows
The Unarchiver
FREE macOS
FAQ
How do I open a ZIP file?
On Windows and macOS, just double-click it — the OS handles ZIP natively. On Windows you can also right-click and select 'Extract All'. For advanced features, use 7-Zip (free).
What is the difference between ZIP and RAR?
ZIP is universal — every OS opens it natively. RAR often compresses slightly better but requires third-party software to open. Use ZIP when you want maximum compatibility. Use RAR if you need better compression and know your recipient has the tools.
How do I password-protect a ZIP file?
On Windows, use 7-Zip: right-click → 7-Zip → Add to Archive, then set a password and choose AES-256 encryption. On macOS, use the Terminal command: zip -e archive.zip files. Avoid the older ZipCrypto method — it can be cracked.
What is the difference between ZIP and 7Z?
7Z (7-Zip) typically achieves 10–30% better compression than ZIP using the LZMA2 algorithm. But 7Z requires 7-Zip or compatible software to open, while ZIP works everywhere. For archiving your own files, 7Z saves space. For sending files to others, ZIP is the safer bet.
Learn more about .zip
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