Units in UV Editor (Imperial to Metric) as per title, is it possible during image export and during editing to use the metric unit system instead of the default imperial system in the UV editor window

I'm using blender 2.80.44 Beta (this question also applies to previous version, i have the same issue there too)

thank you guys (and girls)
In the UV editor the units are either pixels (default is a 256 x 256 pixel square) or when Normalized is checked the square is 0.0 to 1.0.