How can I find an object's height?

How can I find an object’s height in the world coordinates? I want to use the height mainly to subtract from the object’s current y-position in the world coordinate. Hence, the height has to be in the same metrics as the position vector. I tried localScale but it doesn’t work correctly.

i know my answer sounds a bit wrong but i would add 2 emptys to the object your trying to find the height for (one on the top of it and one at the bottom). then just do

Vector3.Distance(top, bottom);

Take a look at Renderer.bounds. This is the bounding box in world space around your object. You should be able to get the size by:

var height = renderer.bounds.extents.y * 2.0;