The best free file comparison programs for Windows

It can be important to compare different versions of a file. Maybe you want to make sure that a file you burned to disc or stored in a backup is identical to the original, list all changes that someone else made to a file, or compare files after a hacking attack to find out if they have been modified in any way by the hacker.

File comparison tools are one option to do so. These programs provide you with the means to compare one or multiple files quickly which is one advantage that they have over comparing data manually.

Some online services, Dropbox, Google Drive or OneDrive, support file revisions as well and can display differences in file versions, but that requires that you use these services and have an Internet connection at your disposal to do so.

Plus, you'd have upload all files you want to check to the service regularly so that you can compare different versions when the need arises.

We take a look at the best file comparison tools for Windows. As usual, we start with the requirements for these tools which all programs have to meet.

Reviews of each program follow, then the comparison table that compares important metrics and finally a recommendation based on the reviews and features.

Requirements

• The software program needs to be fully compatible with all recent 32-bit and 64-bit versions of the Windows operating system.
• A free version needs to be available.
• The core feature of the program needs to be file comparison. This means that text editors with file comparison modules are not included in the list.

The top list

AptDiff

AptDif is a visual file comparison tool for Windows. It displays a prompt on start that you use to select two files that you want to compare and whether you want to compare textual or binary contents.

Both selected files are displayed in the interface afterwards. The application uses colors that indicate added, deleted or changed contents in either file.

You can switch the layout from vertical to horizontal if you prefer it that way and edit one or both files directly in the program window.

Update: The AptDiv website is no longer available. You can still download the program from third-party download sites like Softpedia.

DiffMerge

DiffMerge does not display a file selection dialog on start. You need to select one of the supported modes, folder diff, file diff or file merge from the file menu to get started.

File diff and merge work similar to other file comparison tools. If you select diff, both files are displayed next to each other. The program uses the color red to highlight differences between the two selected files.

You can edit the files right away in the program, export the differences, or use the merge tool to merge the data.

The folder diff utility on the other hand compares files in the selected folders and highlights which are identical and which differ.

Diffuse

Diffuse has been designed specifically for the comparison of code. It supports a couple dozen programming and scripting languages out of the box and uses syntax highlighting automatically when it recognizes a language.

There does not appear to be an option to change the color coding though and some users may find the way things are displayed too colorful to be useful.

As you can see on the screenshot, there is color everywhere making it difficult to spot the differences at times. The program supports the merging of files and the editing of selected files as well.

ExamDiff

The free version of ExamDiff is available as a portable program and installer. It displays a prompt to pick two files on the system on start and displays them next to each other in the interface afterwards.

Here it highlights all differences using colors to indicate added, deleted and changed lines. A menu at the top enables you to jump to any difference spotted by it directly.

Files can be edited directly in the program window and a Unix diff file can be saved as well using the files menu.

KDiff3

KDiff3 displays a prompt on start that you use to load one, two or three files that you want to compare. The files are displayed next to each other in the interface afterwards and when you scroll, all of them do.

The program uses colors to indicate changes on either side. Plain black on white text indicates identical lines or characters while green, blue or red colors indicate that information are not available in all files.

Besides options to compare files with each other, it is also possible to merge selected information in various ways. It is for instance possible to prioritize information in one file or configure the program to resolve basic differences automatically to save time.

Meld

Meld requires that Python 2 is installed on the system. It ships with it and will install the components it requires unless you uncheck that option during installation.

The software supports two- and three-way file comparisons, folder comparisons, and supports a version control view that you can make use of as well.

It highlights differences between loaded files directly and uses colors to visualize those in its interface. What sets it apart from the majority of comparable solutions is the fact that it visualizes how blocks relate to each other in both files.

Merge supports the merging of files and a variety of other options such as tabs to load multiple comparisons at once.

tkdiff

Tkdiff is a graphical front end to the diff program. You can use it to load two files which it displays next to each other afterwards. Each difference is listed in a small menu at the top left corner which you can use to jump straight to it.

Options are provided to edit files directly in the tkdiff interface and to change how things are displayed in it as well. It is for instance possible to disable the scrollbar synchronization or to mark the current diff.

The program supports the merging of files loaded in its interface as well.

WinMerge

WinMerge has been around for a very long time. The program is available as a portable version or installer for Windows. You can use it to compare two different files that you load into it.

Differences are color coded and options are provided to edit files directly in the program window, or to use the merging tools to merge information from two files.

The software supports a large number of comfortable features such as support for bookmarks, plugins, options to generate reports or change how information are displayed in the interface.

Tip: WinMerge 2011 is an official fork that is in active development.

Comparison Table

Name	Portable	Features	Other
AptDif	no	Compare as binary or text
DiffMerge	yes	Folder Diff, Merging, Export	Linux and Mac versions
Diffuse	no	N-way file merge	Linux and Mac versions
ExamDiff	yes		Command line interface
Kdiff3	no	two and three-way comparison	Command line tools, Linux and Mac versions
Meld	yes	two and three-way comparison, Merging, Folder Diff	Linux and Mac versions, requires Python 2
tkdiff	no	Merging	Linux and Mac versions
WinMerge	yes	Merging, folder diff	Plugin support

Recommendation

So which file comparison tool is right for you? I cannot answer that but I can give you recommendations instead. The tool that impressed me the most is Meld. While it requires the installation of Python 2, it supports a lot of different features, is available cross-platform, and supports folder diff on top of all that.

Also, and that may be equally important, it is updated frequently. A lighter option to that is Kdiff3 which worked well during tests, and if you require binary comparison of files, you may want to check out Aptdif instead.

Now You: Use another tool to compare files? Feel free to share it with all of us in the comment section below.

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