# QT license type in Slicer and commerical use question?

**URL:** <https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364>\
**Category:** Support\
**Tags:** qt\
**Created:** [July 18, 2022, 11:27am UTC](https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364 "2022-07-18T11:27:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![StephenLeePeng](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/stephenleepeng/32/11892_2.png) [@StephenLeePeng](https://discourse.slicer.org/u/StephenLeePeng)\
**Post date:** [July 18, 2022, 11:27am UTC](https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364/1 "2022-07-18T11:27:52Z")

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Hi everybody.  
As QT is GUI Framework for Slicer, and QT has two types license, LGPL and GPL.  
LGPL includes: Core, Widgets, QML and so on.  
GPL includes Qt Chats and so on.

As I develop a product, built as an extension, running on Slicer platform. I change some logo, or view controller font in C++, others codes are written by Python.

So I want to know, the product of extension can be used in commerical without open source? @lassoan

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 18, 2022, 1:09pm UTC](https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364/2 "2022-07-18T13:09:09Z")

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We don’t use any GPL-licensed components for building 3D Slicer. You are free to use it for commercial purposes, for free, without asking permission from anyone.

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [July 18, 2022, 6:26pm UTC](https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364/3 "2022-07-18T18:26:38Z")

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Note also that if you choose to use GPL licensed portions of Qt or use Qt in a way that is inconsistent with the terms of the LGPL you may need a commercial license to Qt. For a commercial product this is generally not a problem so you should do it if required by the terms of the licenses.

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**Author:** ![jcfr](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jcfr/32/17825_2.png) [@jcfr](https://discourse.slicer.org/u/jcfr)\
**Post date:** [July 18, 2022, 8:06pm UTC](https://discourse.slicer.org/t/qt-license-type-in-slicer-and-commerical-use-question/24364/4 "2022-07-18T20:06:25Z")

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The following page is useful to find out which licenses are used by each Qt components and dependencies. See [Licenses Used in Qt | Qt 5.15](https://doc.qt.io/qt-5/licenses-used-in-qt.html)