How to install QtDesigner?

You can install and find QT Designer as follows (Windows environment):

• Install latest QT (I'm using 5.8) from QT main site
• Make sure you include "Qt 5.8 MinGW" component
• QT Designer will be installed in C:\Qt\5.8\mingw53_32\bin\designer.exe
• Note that the executable is named "designer.exe"

UPDATE - there is an easier way to install QT Designer without downloading GB's of data from QT:

• Install the latest version of "pyqt5-tools" using pip install pyqt5-tools --pre

• The "designer.exe" will be installed in ...Lib\site-packages\pyqt5_tools

If you are on macOS and use brew you may have installed qt already using brews installer.

In that case you already have QT Designer installed even though it is not mentioned anywhere.

You can find it here: /usr/local/Cellar/qt/<qtversion>/libexec/Designer.app

So to place it in your local apps folder you can create a symlink to it like this:

ln -sf /usr/local/Cellar/qt/5.11.1/libexec/Designer.app ~/Applications/.