.zip — ZIP Archive
Archive application/zip
What a .zip file is
The most widely supported compressed archive format, dating to 1989.
How to open it
Built into Windows, macOS and every Linux desktop.
Worth knowing
DOCX, XLSX, EPUB, JAR and APK are all ZIP files with a different extension and a required internal structure.
How to identify a .zip file
A file's extension is only its name — renaming a.png to a.zip changes nothing inside. What software actually reads is the magic number, the first few bytes of the file.
| Signature | 50 4B 03 04 |
| MIME type | application/zip |
| Category | Archive |
ASCII "PK", after Phil Katz who created the format.
# what is this file really?
file mystery.zip
# look at the first bytes yourself
xxd mystery.zip | head -2
head -c 16 mystery.zip | xxd
# Windows PowerShell
Get-Content mystery.zip -AsByteStream -TotalCount 16 | Format-HexFrequently asked questions
What is a .zip file?
The most widely supported compressed archive format, dating to 1989.
How do I open a .zip file?
Built into Windows, macOS and every Linux desktop.
Is .zip safe to open?
The archive itself is inert, but its contents may not be. Extracting a .zip from an unknown sender is how a lot of malware arrives — check what is inside before running anything.
Can I change a file's extension to convert it?
No. Renaming changes the label, not the bytes. The one place it appears to work is between formats that genuinely share a container — renaming .docx to .zip works because a DOCX is a ZIP. Everything else needs a real converter.