Texel Density Checker is toolset for working with Texel Density.
With Texel Density Checker you can:
Texel Density Checker simple for use. You need select your mesh (or faces) and texture size and just click button.
If you want to support the development of the addon you can do it on Superhive or Gumroad
This extension does not require special permissions.
The best texel density addon for Blender I suppose.
Extremely useful extension and straight forward to use.