What is a ZIP file?
ZIP bundles files and folders into one archive and compresses each entry, usually with the Deflate algorithm. Created by Phil Katz in 1989, the format is built into Windows, macOS, Linux, iOS and Android, so a ZIP is the safest way to send several files to someone whose software you do not know. Office documents, Java JARs, Android APKs and EPUB books are all ZIP files with a different extension.
Each entry is compressed on its own and listed in a central directory at the end of the file, which allows a single file to be extracted without reading the rest. The price is compression ratio: solid archives such as 7Z or TAR.XZ compress many similar files together and end up noticeably smaller. Legacy ZIP encryption is weak; only AES-encrypted ZIPs made by modern tools are secure.
When ZIP is the right choice
Strengths
- Opens without extra software on every operating system
- Random access: extract one file without unpacking everything
- Fast to create and to extract
Limitations
- Weaker compression than 7Z or TAR.XZ, especially on many small files
- Traditional ZipCrypto password protection is easily broken
- Old tools mishandle file names with non-Latin characters
How to open a ZIP file
Double-click on Windows or macOS, or use the built-in tools on your phone. When a ZIP refuses to open or shows garbled file names, Extract ZIP unpacks it in the browser and lists the contents.
How to convert a ZIP file
ZIP to 7Z re-compresses an archive into a smaller solid file, ZIP to TAR.GZ or ZIP to TAR.XZ prepare it for Linux servers, and Extract ZIP unpacks it. Archives coming from the Unix world convert back with 7Z to ZIP.