To compress files, you often use winzip or winrar. Howerver, there are some very powerfully free compression software. Look top 5 rated free compression software.

7-Zip 

The main features of 7-Zip: High compression ratio in new 7z format with LZMA compression. Supported formats: Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR; Unpacking only: RAR, CAB, ISO, ARJ, LZH, CHM, Z, CPIO, RPM, DEB and NSIS. For ZIP and GZIP formats 7-Zip provides compression ratio that is 2-10 % better than ratio provided by PKZip and WinZip. Self-extracting capability for 7z format. Integration with Windows Shell. Powerful File Manager. Powerful command line version. Plugin for FAR Manager.

ALZip

ALZip is a one-stop archiving and compression program designed for speed and ease of use. Beginners can easily perform advanced tasks, while power users can do things faster. With support for more compression and archiving formats than any other major utility, ALZip is the only ZIP utility you'll ever need. You can open 36 archive and compression file formats, open CD image files (ISO, BIN), open virtual CD files (LCD), create 8 archive and compression file formats, create self-extracting files (EXE), split files for easy transfers, recover lost passwords from ZIP files, integrate antivirus software, automate tasks with ALZip command-line functions, and get more done faster. The ALTools family of free PC utilities share the same cute Egghead characters, are a fun addition to any computer, are ideal for children, and powerful enough for IT pros.

ExtractNow

ExtractNow allows you to extract more than one archived file at a time, with one click of a button. It makes extracting files quicker and easier. ExtractNow supports ZIP, RAR, ACE, IMG, IMA, IMZ, ISO, and BIN, and archives.

IZArc

IZArc is the ultimate freeware archive utility supporting many archive formats. With a modern easy-to-use interface, IZArc provides support for most compressed and encoded files, as well as access to many powerful features and tools. It allows you to drag and drop files from and to Windows Explorer, create and extract archives directly in Windows Explorer, create multiple archives spanning disks, creating self-extracting archives, repair damaged zip archives, converting from one archive type to another, view and write comments. IZArc has also build-in multi language support.

PeaZip

PeaZip is an open source portable file archiver, released under LGPL for Windows and Linux. Full support: 7Z, 7Z-sfx, BZip2, GZip/TGZ, PAQ8F, PAQ8JD, PAQ8L, PEA, QUAD, split (.001), TAR, ZIP. PeaZip allows to: browse archives (with multiple inclusion and exclusion filters), extract multiple archives at once, save archive's layout, save job definition (to be inspected, or used in scripts), save job log. PeaZip can be used also to split/merge files in multiple volumes, to compress executables with split/UPX and to generate random passwords and keyfiles.

Most used functions are also available in SendTo and context menu (Windows). The interface is customizable for opacity, some colors, and icons. Version 1.8 adds updated front-end to use 7z 4.47 beta, support for archiving open for writing files, fast Deflate and Deflate64, read/write AES encrypted ZIP files (WinZip AE standard and read support for ACE archives.

C/NET