Qt Licensing

Qt is available under three different licensing options designed to accommodate the needs of our various users.

Qt licensed under our commercial license agreement is appropriate for development of proprietary/commercial software where you do not want to share any source code with third parties or otherwise cannot comply with the terms of the GNU LGPL version 2.1 or GNU GPL version 3.0.

Qt licensed under the GNU Lesser General Public License (LGPL) version 2.1 is appropriate for the development of Qt applications provided you can comply with the terms and conditions of the GNU LGPL version 2.1.

Qt licensed under the GNU General Public License (GPL) version 3.0 is appropriate for the development of Qt applications where you wish to use such applications in combination with software subject to the terms of the GNU GPL version 3.0 or where you are otherwise willing to comply with the terms of the GNU GPL version 3.0.

Qt documentation is licensed under the terms of the GNU Free Documentation License (FDL) version 1.3, as published by the Free Software Foundation. Alternatively, you may use the documentation in accordance with the terms contained in a written agreement between you and Digia.

Please see http://qt.digia.com/licensing for an overview of Qt licensing.

Purchasing and Sales Information

To purchase or further information and assistance about Qt commercial licensing, please contact Digia Qt sales via one of the following channels:

Web:http://qt.digia.com/contact-us
Phone, U.S. office (for sales in North America):+1 408 433 9320
Phone, Norway office (for sales in the rest of the world):+47 2108 0420

Licenses Used in Qt

The following table lists the other licenses used in Qt, not provided under the GNU General Public License (GPL), GNU Lesser General Public License (LGPL) or the Qt Commercial License. Third-party licenses used in libraries that are supplied alongside Qt modules are also listed.

Note: Cross-module dependencies are also described on a general level. All Qt modules depend on Qt Core.

Qt Module/ToolComponentDescriptionLicense TypeNotes
Qt Core
QCrashHandlerParts of implementation of QCrashHandler class.BSD-style
QUrlImplementation of QUrl::fromUserInput().Modified BSD
Cocoa Platform PluginSpecific parts of the Qt for Mac OS X Cocoa port.BSD-styleQt for Mac OS X
qtmain libraryA helper library for writing a cross-platform main() function on Windows.Modified BSDQt for Windows
DESImplementation of DES encryption (des.cpp).MIT
Shift-JIS Text CodecA character encoding for Japanese.BSD-style
ISO-2022-JP (JIS) Text CodecA widely used encoding for Japanese.BSD-style
EUC-JP Text CodecEUC-JP is a variable-width encoding used to represent the elements of three Japanese character set standards.BSD-style
EUC-KR TextCodecExtended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese.BSD-style
GBK Text CodecGBK is an extension of the GB2312 character set for simplified Chinese characters, used mainland China.BSD-style
Big5 Text CodecBig5, or BIG-5, is a Chinese character encoding method used for Traditional Chinese characters.BSD-style
TSCII Text CodecThe TSCII codec provides conversion to and from the Tamil TSCII encoding.BSD-style
Stack-less Just-In-Time compilerA platform-independent JIT compiler.BSD
Parts of the codecs implemented by QtBSD
UnicodeUnicode character data.Permissive, GPL-compatible
Macros for building Qt filesMacros used in CMake files for building Qt.BSD
The PCRE libraryThe PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5.BSD-style
Third-party Licenses
Android C++ Run-timeGNU C++ run-time library (libstdc++) for Android.GPLv3 with exceptionQt for Android
MD4implements the MD4 message-digest algorithm.BSD
MD5implements the MD5 message-digest algorithm.BSD
SHA-1implements the SHA-1 encryption algorithm.BSD
SHA-3implements the SHA-3 encryption algorithm.BSD
zlibzlib is a general purpose data compression library.BSD-style
Qt Gui
QKeyMapperInternal class for key mapping.Custom, BSD-styleQt for Linux/X11
Third-party Licenses
FreeTypeParts of FreeType project used in font rendering.GPLv2, FreeType Project License
Third-party Licenses
HarfBuzzOpenType layout engine.BSD-style
FreeType 2Parts of FreeType project used in font rendering.GPLv2, FreeType Project License
PNG Reference LibraryA library for reducing the time and effort it takes to support the PNG format.BSD-style
PixmanPixman is a library that provides low-level pixel manipulation features such as image compositing and trapezoid rasterization.BSD-style
Drag and DropAllows users to transfer information between and within applications.BSD-style
ANGLEOpensource project to map OpenGL ES API calls to DirectX API.BSD-styleQt for Windows
Qt Location
Third-party Licenses
Poly2TriPoly2Tri is a sweepline constrained Delaunay Polygon Triangulation Library.BSD-style
Qt Network
Third-party Licenses
The Public Suffix ListA list of all known public Internet suffixes.Mozilla Public License
Qt Multimedia
Third-party Licenses
FFTRealFast Fourier transform of real-valued arrays.LGPL(Used in example code).
Qt SVG
Qt SVG License InformationParts of code for arc handling in Qt SVG module.BSD-styleDepends on Qt Gui, Qt Widgets
Qt Quick
Third-party Licenses
Easing EquationsEasing Equations is a collection of swappable functions that add flavor to motion.BSD-styleDepends on Qt QML, Qt Gui, Qt Network
Qt Script(Provided for Qt 4 compatibility)
V8 benchmark testsV8 benchmark tests used in Qt Script.BSD-style
Sunspider benchmark testsSunspider benchmark tests used in Qt Script.BSD-style
Third-party Licenses
JavaScriptCoreBSD-style
Qt Test
TestlibParts of implementation of Qt Test library.BSD, MIT
Third-party Licenses
ValgrindA code analysis tool for detecting memory leaks.GPL v2
valgrind.h specific licenseBSD-style
CallgrindA performance profiling tool.GPL v2
Qt Print SupportDepends on Qt Gui and Qt Widgets
PDF LicensingNotes about PDF Licensing.
Qt WebKit
WebKit used by the QtWebKit moduleParts of WebKit used by the QtWebKit moduleBSD-styleDepends on Qt Gui, Qt Network, Qt SQL, Qt QML, and Qt Quick
Third-party Licenses
WebCoreA layout, rendering, and Document Object Model (DOM) library for HTML and SVG.LGPL, MIT, BSD-style
Qt Designer
Qt Designer License InformationImplementation of the recursive shadow casting algorithm in Qt Designer.BSD (MIT)
Qt Creator
Third-party Licenses
BotanA C++ crypto library used in Qt Creator.BSD
Qt Image Formats
Third-party Licenses
TIFFlibtiff is a set of C functions (a library) that support the manipulation of TIFF image files.BSD
MNGSupport decoding and displaying of MNG format image files.BSD-style
Qt SQL
SQLiteA C library that implements a self-contained, embeddable, zero-configuration SQL database engine.BSD-style
Qt XML Patterns
Bison ParserBison is a parser generator.GPL with exceptionDepends on Qt Network
Plugins
JPEGC software to implement JPEG image compression and decompression.BSD-style
IAccessible2An accessibility API for Microsoft Windows applications.BSDQt for Windows
CycleA CPU tick counter.MIT
callgrind.h specific licenseBSD-style
xcbA C language binding for the X Window System.BSD-styleQt for Linux/X11
at-spi and at-spi2A toolkit-neutral way of providing accessibility facilities in application.LGPLQt for Linux/X11
xkbcommonKeymap handling library for toolkits and window systems.BSD-styleQt for Linux/X11
Qt Tools
Third-party Licenses
Clucene Core LibraryA high-performance, full-featured text search engine written in C++.LGPL/Apache

Additional information

The documents below list related documents, such as information about Trademark and other licenses used in parts of Qt.

Notes about PDF Licensing

Details of restrictions on the use of PDF-related trademarks.

Qt SVG License Information

License information for Qt SVG

Third-Party Licenses Used in Qt

License information for third-party libraries supplied with Qt.

Android GNU C++ Run-time Licensing

Provides additional information about the licensing of run-time dependencies of Qt for Android

Licenses for Fonts Used in Qt for Embedded Linux

Information about the licenses of fonts supplied with Qt

Open Source Licensing of Qt

Information about open source licensing of Qt.

Trademarks

Information about trademarks owned by Digia and other organisations.

The qtmain Library

Describes the use and license of the qtmain helper library.

Contributions to the Cocoa Platform Plugin Files

License information for contributions by Apple, Inc. to specific parts of the Qt for Mac OS X Cocoa port.