estimation vs calculation

estimation and calculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
estimation	Yes	No	No	No
calculation	Yes	No	No	No

As nouns, calculation is a hypernym of estimation; that is, calculation is a word with a broader meaning than estimation:

Other hypernyms of estimation include computation, figuring, reckoning.

estimation (noun)	calculation (noun)
a judgment of the qualities of something or somebody	the procedure of calculating; determining something by mathematical or logical methods
an approximate calculation of quantity or degree or worth	problem solving that involves numbers or quantities
the respect with which a person is held	planning something carefully and intentionally
a document appraising the value of something (as for insurance or taxation)