Qt Licensing

The Qt Licensing Model

Our aim with Qt is to make it available to as many developers as possible while helping it evolve and grow. We have chosen three licensing options that directly or indirectly help us continue to evolve Qt.

Qt Licenses

We offer Qt under the following licenses:

Qt Commercial Version	The Qt Commercial version is the appropriate version to use for the development of proprietary and/or commercial software. This version is for developers who do not want to share the source code with others or otherwise comply with the terms of the GNU Lesser General Public License version 2.1 or GNU GPL version 3.0.	Read more
Qt GNU LGPL v. 2.1	This version of Qt is appropriate for the development of Qt applications (proprietary or open source) provided you can comply with the terms and conditions contained in the GNU LGPL version 2.1.	Read more
Qt GNU GPL v. 3.0	This version of Qt 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 General Public License version 3.0 or where you are otherwise willing to comply with the terms of the GNU General Public License version 3.0.	Read more

License Comparison Chart

	Commercial version	LGPL version	GPL version
License cost	License fee charged	Free	Free
Must provide source code changes to Qt	No, modifications can be closed	Source code must be provided	Source code must be provided
Can create proprietary applications	Yes - No source code must be disclosed	Yes, in accordance with the LGPL v. 2.1 terms	No, applications are subject to the GPL and source code must be made available
Updates provided	Yes, to those with valid maintenance	Yes, freely distributed	Yes, freely distributed
Support	Yes, with valid maintenance agreement	Not included but available for purchase separately	Not included but available separately for purchase
Charge for Runtimes	Yes	No	No

Qt Commercial License

The Qt Commercial License is the correct license to use for the development of proprietary and/or commercial software with Qt where you do not want to share any source code.

You must purchase a Qt Commercial License from Qt Software or from one of its authorized resellers before you start developing commercial software. The Commercial license does not allow the incorporation of code developed with the Qt GNU LGPL v. 2.1 or GNU GPL v. 3.0 license versions into a commercial product.

Royalties and Runtimes
For regular desktop applications, there are no royalties, runtime licenses, or other additional costs. For fixed systems or devices where the main functionality relies on Qt, a runtime distribution license may apply.

Purchase and Transfer of Commercial Licenses
The license is sold on a per-developer basis and assigned to an individual. To order one or more Qt Commercial Licenses please contact us. Qt licenses may be transferred, but only every six months and within the same organization. To transfer a license, or to discuss a more flexible licensing agreement, please contact us.

Benefit to Qt
The benefit to Qt is that license fees help pay for further Qt development.

Qt GNU LGPL v. 2.1 Version

This version is available for development of proprietary and commercial applications in accordance with the terms and conditions of the GNU Lesser General Public License version 2.1.

Support services are available separately for purchase.

Benefit to Qt
The benefit to Qt is that any changes made to Qt must be made available under the terms of this license.

Qt GNU GPL v. 3.0 Version

This version is freely available for the development of open source software governed by the GNU General Public License version 3.0 (“GPL”).

This version is available for the development of open source Software for Windows, Linux, Unix, and Mac OS X under the GPL. Please note the following:

We provide the Qt GNU GPL v. 3.0 version with no warranty. Support is available separately for purchase.
The Qt GNU GPL v. 3.0 version may be freely copied and distributed, put on FTP sites and CD-ROMs, etc. under the terms of the GPL.
Based on the "Quid Pro Quo" principle, if you wish to derive a commercial advantage by not releasing your application under an open source license, you must purchase an appropriate number of commercial licenses from Qt Software before you begin developing commercial software. By purchasing commercial licenses, you are no longer obliged to publish your source code.
If you wish to use the Qt Open Source Edition, you must contribute all your source code to the open source community in accordance with the GPL when your application is distributed.