Qt Licensing

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

  • Qt licensed under commercial licenses are 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 3.
  • Qt licensed under the GNU Lesser General Public License (LGPL) version 3 is appropriate for the development of Qt applications provided you can comply with the terms and conditions of the GNU LGPL version 3 (or GNU GPL version 3).

Note: Some specific parts (modules) of the Qt framework are not available under the GNU LGPL version 3, but under the GNU General Public License (GPL) instead. See Licenses Used in Qt for details.

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 The Qt Company.

See http://qt.io/licensing/ for an overview of Qt licensing.

Purchasing and Sales Information

To purchase a Qt license, visit http://www.qt.io/download/.

For further information and assistance about Qt licensing, contact our sales; see http://www.qt.io/locations/ for contact details.

Licenses Used in Qt

The following table lists parts of Qt that incorporate code licensed under licenses other than GNU Lesser General Public License (LGPL) or the commercial license, as well as Qt modules that are only available under a specific license or a version of a 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
QSegfaultHandlerParts of implementation of QSegfaultHandler class.BSD-style
QUrlImplementation of QUrl::fromUserInput().Modified BSD
Cocoa Platform PluginSpecific parts of the Qt for macOS Cocoa port.BSD-styleQt for macOS
qtmain libraryA helper library for writing a cross-platform main() function on Windows.Modified BSDQt for Windows
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
Big5-HKSCS Text CodecBig5-HKSCS is a Chinese character set with more than 4700 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
forkfdA tool to facilitate spawning sub-processes.MITUnix systems
FreeBSD strtoll and strtoullFunctions for converting a string to long long integer.BSD
V8 double/string conversion libraryFunctions for converting between strings and doubles.BSD
MD4implements the MD4 message-digest algorithm.BSD
MD5implements the MD5 message-digest algorithm.BSD
Mesa llvmpipeMesa llvmpipe software rasterizer backend (opengl32sw.dll) for Windows builds.MITQt for Windows
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
The Public Suffix ListA list of all known public Internet suffixes.Mozilla Public License
Qt Gui
QKeyMapperInternal class for key mapping.Custom, BSD-styleQt for Linux/X11
QImageCode used for smooth scaling in QImage::transformed().BSD
Third-party Licenses
FreeTypeParts of FreeType project used in font rendering.GPLv2, FreeType Project License
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
ClipperClipper is a freeware library for clipping and offsetting lines and polygons.BSD-style
Clip2TriClip2Tri is an open source polygon triangulation library based on Poly2Tri.MIT
Qt Bluetooth
Third-party Licenses
BlueZBlueZ is a Bluetooth stack for Linux based operating systemsGPL v2Used by sdpscanner tool which is called by Qt Bluetooth on BlueZ 5 systems. Qt applications do not link to GPL code.
Qt Multimedia
Third-party Licenses
FFTRealFast Fourier transform of real-valued arrays.LGPL(Used in example code).
Qt Canvas 3D
Third-party Licenses
three.jsJavaScript 3D libraryMIT(Used in example code)
Three.js LoaderA parser for loading 3D models from JSON data structures.MIT(Used in example code).
gl-matrix.jsHigh performance matrix and vector operationsMIT(Used in example code).
Qt SVG License InformationParts of code for arc handling in Qt SVG module.BSD-styleDepends on Qt Gui, Qt Widgets
Third-party Licenses
JavaScriptCore Macro AssemblerThe assembly code generated use by the JIT.BSD-style
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 Quick Controls
Native Style for AndroidApache License 2.0Qt for Android
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
JavaScriptCoreLGPL v2
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 Wayland
Wayland ProtocolMIT
Qt WebEngine
Qt WebEngine CoreLGPL v3 or
GPL v2 + Qt commercial license
Third-party Licenses
ChromiumThird-party licenses in ChromiumLGPLv2.1, BSD, BSL, Apache, APSL, MIT, MPL, othersSee Qt WebEngine Licensing for details.
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
JasPerA collection of software for the coding and manipulation of images.BSD-style
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
WebPSupport decoding and displaying of WebP format image files.BSD-style
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
Qt 3D
Third-party Licenses
assimpOpen Asset Import LibraryBSD
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

The following modules are available under the GNU GPL version 3 and commercial licenses:

Qt Module/ToolComponentDescriptionLicense Type
Qt ChartsGPLv3 or commercial license
Qt Data VisualizationGPLv3 or commercial license
Qt PurchasingGPLv3 or commercial license
Qt Virtual KeyboardGPLv3 or commercial license
Third-party Licenses
Lipi ToolkitAn open source toolkit for online Handwriting Recognition (HWR).MIT-Style License
OpenWnnA Japanese IMEApache License
PinyinAn IME for Standard Chinese input.Apache License
tcimeA traditional Chinese IME.Apache License
Qt Quick 2D RendererGPLv3 or commercial license
Third-party Licenses
EGL 1.5 HeadersThese headers are based on EGL 1.5 specification.MIT License
OpenGL ES 2.0 HeadersThese headers are based on OpenGL ES 2.0 specification.MIT and SGI License
OpenGL ES 3.1 HeadersThese headers are based on OpenGL ES 3.1 specification.MIT and SGI License
OpenKODE Core 1.0 HeaderThe header is based on OpenKODE Core 1.0 specification.MIT License
V8 double/string conversion libraryString conversion routines for IEEE doubles.BSD-style

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.

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.


Information about trademarks owned by The Qt Company and other organizations.

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 macOS Cocoa port.

Qt SVG License Information

License information for Qt SVG

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.