Best Free File Comparison Utility

file comparison utility helps you visually compare and merge the differences between two (or more) different versions of the same file, or detect the variations between two different sets of data. These types of utilities are often called "Diff" programs. Hundreds of different types of file comparison utilities exist, each tailored for specific types of data and file formats.

If you are looking to compare plain text files such as code or binary files many different free choices exist. One of the best is WinMerge. It only runs on a Windows based system, but it can handle DOS, UNIX, and MAC, text file formats. A version of WinMerge called WinMergU also supports Unicode. WinMerge can integrate with Windows Explorer and will compare two corresponding groups of text files, and tell you which are identical and which have differences. It will also compare two individual files and like most diff utilities it shows the files being compared in two vertical panes and highlights the differences, allowing you to merge or ignore the changes. While WinMerge is an excellent text file comparison utility it will not work with word processor or spreadsheet type documents because they include special formatting and markup. For these types of files you need a comparison program that is especially designed to support their formatting. Unfortunately virtually all of these come with an exorbitant price tag, which puts them out of the reach of most users.

Another good product is KDiff3. It is similar to WinMerge with many of the same features, but also supports other operating systems including GNU/Linux, Unix, and Mac OSX.

WinMerge
Website: http://winmerge.org
Download link: http://winmerge.org/downloads/index.php
Current version: 2.6.14
Version date: January 17th 2008
License: Freeware
Download File Size: 2.9 MB
Operating Systems Supported: MS Windows (95/98/NT/2000/XP/Limited Vista support)
Additional Software Required: 7-Zip Plug-in (for archive support)
64 Bit Capable: Limited 64-bit support
Portable Version Available: No

KDiff3
Website: http://kdiff3.sourceforge.net
Download link: http://sourceforge.net/project/showfiles.php?group_id=58666
Current version: 0.9.92
Version date: April 15th 2007
License: Freeware
Download File Size: 7MB
Operating Systems Supported: MS Windows, GNU/Linux with KDE3,Unix, Mac OSX
Additional Software Required: none
64 Bit Capable: unverified
Portable Version Available: No