What is the default height on Androids TabLayout

Material Design guidelines state that this height equals 48dp when You have text or image, and 72dp when You have image and text.

its height is "?attr/tabIndicatorHeight"

E.g. you can use this value in an xml file for another view like:

android:layout_marginBottom="?attr/tabIndicatorHeight"

And it will look ok on all devices.