The default spacing of child items inside containers is 0 px for positioners and 5 px for layouts. However, those values should adapt to the chosen style. For example, the default spacing in the Qt Widget Fusion theme is 6 px, as defined in QCommonStyle . Microsoft's Universal style guidelines require all spacing to be multiples of 4 px , and the default spacing is 12 px . The required spacing can be set manually of course, but this is not a solution for platform-independent applications.