User blog comment:Metal Mario875/Mario's Massive Multiverse/@comment-32286613-20170717143340/@comment-26374068-20170717203552

The thirty inhabited universes? The seven from SMG2, the ten from SPM, the Paranormal Dimension's ten, Smithy's Dimension, Vanda and our universe.

The fifteen that are uninhabited are the Secret Levels from Sunshine (which I recently found out to actually be inhabited, btw, so I have to redo this calc at some point), as well as the five from the mansion in Luigi's Mansion.