Introduction to WinMerge

WinMerge is an Open Source differencing and merging tool for Windows. WinMerge can compare two or three folders and files, presenting differences in a visual text format that is easy to understand and handle.

WinMerge is highly useful for determining what has changed between project versions, and then merging changes between versions. WinMerge can be used as an external differencing/merging tool or as a standalone application.

In addition, WinMerge has many helpful supporting features that make comparing, synchronising, and merging as easy and useful as possible. Several programming languages and other file formats are syntax-highlighted.

WinMerge is not a hex editor. WinMerge can show binary files contents and differences between them. But the information is meant for viewing only: editing binary files with WinMerge can break the files.

The goal of WinMerge development is to make comparing, synchronizing, and merging folders and files easy and fast, while maintaining maximum reliability. Ease of use is of key importance for reducing errors.

The latest version 2.16 is considered a stable and reliable program to use.


WinMerge is not freeware (as many sites on the Web have stated): It is GPL licensed.

We provide you with a good tool for free, so please honor your license agreement and submit improvements to us. We are happy to get help improving WinMerge, to the advantage of all WinMerge users.

1. WinMerge versions

There are two kind of versions available in the downloads page.

1.1. Stable versions

Stable versions are recommended for most users. If you are unsure about what version to use, use the latest stable version. Stable versions have an even last number, for example, 2.14.0, 2.16.2 and 2.16.4.

1.2. Beta versions

Beta versions are for people who want to test latest features and improvements made after last stable version. Beta versions are not tested as extensively as stable versions and probably have some bugs. Beta versions have an odd last number, for example 2.16.3 and 2.16.5. Beta versions can be used in production, because they are not expected to have major bugs. But there is always a risk with using beta-level releases, so consider it carefully. We have tried to release a new stable series once a year, so it may be worth waiting for few months for the next stable release...

2. Getting support and reporting bugs

The Discussion forums are the fastest way to get help:

If you find a bug, please submit it as a bug report. Please attach as much information as you can: at a minimum, the version number of WinMerge that you are using. If you can, also attach a configuration log which, you can display by clicking HelpConfiguration in the WinMerge window. Good information in a bug report makes it more likely that your bug will be fixed quickly.


Include the version number in bug reports. You can check the version number by clicking HelpAbout WinMerge.

3. WinMerge source code and development

WinMerge source code is available on our website and from the GitHub project pages. Anyone can download the sources, study them, and alter them. If you find (and fix) bugs, improve something, and so on, please submit your changes to us as patches or pull requests and help improve this product! If you publish your altered version, you are required to publish the changes to source code too. This is what the GPL license is about: please respect it.

WinMerge development work is done by people in their spare time. Nobody gets paid for improving WinMerge. We try to fix bugs as we find them or when somebody reports them to us. We really try - we use WinMerge too. But there are absolutely no promises for new features. We always appreciate any help with WinMerge, be it testing, documenting, translating, or coding.