Filename extension .zip
Internet media type application/zip
Uniform type identifier
Developed by Phil Katz
Type Data compression
File formats category - v  e   edit

The ZIP file format is a data compression and archive format. A ZIP file contains one or more files that have been compressed to reduce file size, or stored as-is. The ZIP file format permits a number of compression algorithms, but as of 2008, only Deflate is widely used and supported.

A ZIP archive is called a Compressed (zipped) folder in Windows.


A ZIP archive stores files in an arbitrary order. The files in the archive (file data) are separately compressed, allowing arbitrary access to individual files.

All files are stored in a "listed" order, "physical" directories are not present. Instead, slashes or backslashes can be specified in the filename, allowing any conversion from "virtual" directories to "physical" directories, and vice-versa.

Each file data is preceded by a local file header containing information about the file such as its filename, and is suceeded by a data descriptor containing information such as the file's compressed size and uncompressed size.

At the end of the archive is a central directory, which contains references to the locations of the local file headers and other information such as encryption information.