What is the exact meaning of a "calculating" person?
The thesaurus may assist.  The Synonyms of 'calculating' are: artful, astute, calculative, canny, conniving, crafty, cunning, deceitful, devious, dexterous, dirty, disingenuous, foxy, guileful, machiavellian, manipulative, scheming, shrewd, slick, slippery, sly, subtle, underhand, unscrupulous, and wily.
Acknowledging that everyone pursues self-interest to an extent, the intent of the definition appears to suggest that a 'calculating' person has little empathy or consideration of others.
Synonyms extracted from Merriam-Webster and Oxford.