WinZip is a proprietary file archiver and compressor

File archiver

A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage...

 for Microsoft Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 and Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

, developed by WinZip Computing (formerly Nico Mak Computing). It natively uses the PKZIP

PKZIP

PKZIP is an archiving tool originally written by Phil Katz and marketed by his company PKWARE, Inc. The common "PK" prefix used in both PKZIP and PKWARE stands for "Phil Katz".-History:...

 format but also has various levels of support for other archive formats.

WinZip has a 45-day free evaluation period, after which the program would still work even if the user had not registered, albeit with reduced functionality.