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KDiff3

apps.kde.org

Free plan Open source WindowsmacOSLinux
Visit apps.kde.org
Spec score 8.3 #8 of 29 in Diff and Merge Tools

What it is

KDiff3 is a free, open-source desktop app for comparing and merging files and folders on Linux, macOS, and Windows. It can compare two or three text files or folders, showing differences line by line and character by character. For merge work, it can combine changes automatically and includes an editor for resolving conflicts, including three-way merges. Folder comparison and Git integration are supported. KDiff3 handles Unicode, UTF-8, and other file encodings; users can highlight or hide whitespace and comment changes, and print differences. It also supports version-control keyword and history merging, with network transparency through KIO. Its listed license is GPL-2.0-or-later. The Free plan costs nothing, and there is no free trial. Linux installation options include Discover or another AppStream store, a distribution package manager, or Flathub. The app page links to a handbook, forum, and bug-reporting page. KDE describes itself as an international community building and distributing free, open-source software since 1996.

Spec sheet

What it does
KDiff3 compares and merges files or folders in a desktop graphical interface.Read 15 Oct 2026 · apps.kde.org
Purpose
KDiff3 compares and merges files and folders.Read 7 Oct 2026 · apps.kde.org
Platforms
The app page lists Linux installation and links to Windows and macOS; nightly installers are listed for Windows and macOS ARM and Intel.Read 7 Oct 2026 · apps.kde.org
License
KDiff3 is distributed under the GNU GPL version 2 or any later version, identified on the product page as GPL-2.0-or-later.Read 15 Oct 2026 · apps.kde.org
Maker
KDE describes itself as an international community building and distributing free, open-source software since 1996.Read 7 Oct 2026 · kde.org
AlternativeTo criticism
AlternativeTo user comparisons describe KDiff3 as less lightweight than Meld and focused on a narrower desktop workflow than broader alternatives.Read 15 Oct 2026 · alternativeto.net
AlternativeTo listing
AlternativeTo categorizes KDiff3 as a free, open-source diff tool and shows 118 community likes.Read 15 Oct 2026 · alternativeto.net
Automatic merging
KDiff3 includes an automatic merge function.Read 15 Oct 2026 · apps.kde.org
Build requirements
The current build instructions require Qt 6.7 or newer, KDE Frameworks 6.2 or newer, CMake 3.22 or newer, ECM 6.2 or newer, Boost 1.71 or newer and a C++17-capable compiler.Read 15 Oct 2026 · github.com
Command-line interface
The project documents command-line syntax for two-way and three-way comparisons and output-file merges.Read 15 Oct 2026 · github.com
Comparison
It compares two or three text files or folders and shows differences line by line and character by character.Read 7 Oct 2026 · apps.kde.org
Conflict editor
An integrated editor lets users resolve merge conflicts interactively.Read 15 Oct 2026 · docs.kde.org
Current release
The KDE application page lists version 1.12.5 released on 2026-07-20.Read 15 Oct 2026 · apps.kde.org
Documentation depth
The official handbook covers file and folder workflows, command-line options, editing, printing, configuration, preprocessors, KIO networking, Git usage, troubleshooting questions and licensing.Read 15 Oct 2026 · docs.kde.org
Encoding support
KDiff3 supports Unicode, UTF-8 and other file encodings.Read 15 Oct 2026 · apps.kde.org
Flathub usage
Flathub reports approximately 543 downloads per month for KDiff3.Read 15 Oct 2026 · flathub.org
Flatpak availability
Flathub offers KDiff3 as a free desktop-only Flatpak for x86_64 and aarch64 architectures.Read 15 Oct 2026 · flathub.org
Folder merge
The handbook documents comparing and merging two or three folders, including per-file operations.Read 15 Oct 2026 · docs.kde.org
Git integration
The documentation includes instructions for using KDiff3 as Git's diff and merge tool.Read 15 Oct 2026 · docs.kde.org
Help and support
The app page links to the KDiff3 Handbook, a forum, and a bug-reporting page.Read 7 Oct 2026 · apps.kde.org
Limit: large binary files
A SourceForge reviewer reports that large binary files are loaded entirely into memory, causing the program to become unresponsive.Read 15 Oct 2026 · sourceforge.net
Limit: missing convenience features
Reviewers request file-list search, summary statistics, direct text input, patch creation and printable difference reports.Read 15 Oct 2026 · sourceforge.net
Limit: performance and UI bugs
Archived issue reports mention slow CSV comparisons, high-resolution display problems, crashes, unsaved conflict resolutions and progress indicators stuck at zero.Read 15 Oct 2026 · sourceforge.net
Line and character diffs
Its viewer identifies changes at both line and individual-character level.Read 15 Oct 2026 · apps.kde.org
Linux installation
Linux users can install through Discover or another AppStream store, a distribution package manager, or Flathub.Read 7 Oct 2026 · apps.kde.org
Maker company facts
LinkedIn lists KDE e.V. as founded in 1997, headquartered in Berlin, with 2–10 employees.Read 15 Oct 2026 · linkedin.com
Maker legal entity
KDE e.V. is a registered German nonprofit representing the KDE community in legal and financial matters.Read 15 Oct 2026 · ev.kde.org
Merging
It provides automatic merging and an editor for resolving merge conflicts.Read 7 Oct 2026 · apps.kde.org
Network access
It provides network transparency via KIO.Read 7 Oct 2026 · apps.kde.org
Network integration
KIO provides network-transparent access, with the handbook covering KIO slaves and URL capabilities.Read 15 Oct 2026 · docs.kde.org
Notable news: infrastructure hiring
KDE e.V. announced a search for a Software Infrastructure and Continuous Delivery Engineer on 2026-09-14 and marked applications closed on 2026-10-05.Read 15 Oct 2026 · ev.kde.org
Praise: integration and usability
Reviewers describe it as easy to integrate with development toolchains, useful for Windows Explorer workflows and lightweight once learned.Read 15 Oct 2026 · sourceforge.net
Praise: merge and comparison capability
SourceForge reviewers repeatedly praise the tool's folder comparison, inline differences, automatic merging and three-way editing.Read 15 Oct 2026 · sourceforge.net
Printing
The product can print difference results.Read 15 Oct 2026 · docs.kde.org
Rating on SourceForge
4.8 out of 5 stars from 39 reviews.Read 15 Oct 2026 · sourceforge.net
Release
The page lists version 1.12.5, dated 2026-07-20, as the latest release shown.Read 7 Oct 2026 · apps.kde.org
Security and privacy
KDE says its software contains no ads, spyware, subscription services, forced updates, secret crypto-mining, or AI training.Read 7 Oct 2026 · kde.org
Source availability
The complete source repository is publicly available under KDE's GitHub organization, with build files, tests and documentation directories.Read 15 Oct 2026 · github.com
Support channels
The product page links users to the handbook, KDE discussion forum, bug tracker and public source repository.Read 15 Oct 2026 · apps.kde.org
Supported desktop systems
Official downloads provide Windows x86-64 installers, macOS Intel and ARM disk images, source archives and Flatpak packages.Read 15 Oct 2026 · download.kde.org
Testing builds
KDiff3 nightly installers are described as intended for testing and generated from the latest development branch.Read 7 Oct 2026 · apps.kde.org
Text handling
It supports Unicode, UTF-8 and other file encodings, and can highlight or hide whitespace and comment changes.Read 7 Oct 2026 · apps.kde.org
Two-way and three-way comparison
The application compares two or three text inputs or folders.Read 15 Oct 2026 · docs.kde.org
Version control
It supports version-control keyword and history merging.Read 7 Oct 2026 · apps.kde.org
Version-control history merging
The handbook describes merging version-control keywords and history information.Read 15 Oct 2026 · docs.kde.org
Whitespace and comment handling
Users can highlight or suppress differences in whitespace and comments.Read 15 Oct 2026 · apps.kde.org

Plans and prices

Free Free Free and open-source software · GPL-2.0-or-later Read 7 Oct 2026 · apps.kde.org
Free open-source KDiff3 Free Desktop file and folder comparison and merging · GPL-2.0-or-later Read 15 Oct 2026 · flathub.org

Every KDiff3 plan and price →

Strong points and limits

Strong points

  • Compares two or three files or folders
  • Includes automatic merging and a conflict editor
  • Supports Unicode, UTF-8, and other encodings
  • Runs on Linux, macOS, and Windows

Limits

  • No free trial is listed
  • Syntax highlighting is not supported

Who it suits

KDiff3 suits people who need to compare text files or folders and resolve merge conflicts. Its support for two- or three-way comparisons, multiple encodings, and version-control history can fit varied merge workflows.

Verdict

KDiff3 provides file and folder comparison alongside merge and conflict-resolution tools across three desktop platforms. Its free, open-source license and linked handbook, forum, and bug-reporting page are useful points to weigh.

Where Specifiction places it

Alternatives to KDiff3All alternatives →