calculator vs estimator

calculator and estimator both are nouns.

Word	Noun	Adjective	Verb	Adverb
calculator	Yes	No	No	No
estimator	Yes	No	No	No

As nouns, calculator and estimator are synonyms defined as:

calculator and estimator: an expert at calculation (or at operating calculating machines)

Other synonyms of calculator include computer, figurer, reckoner.

calculator (noun)	estimator (noun)
a small machine that is used for mathematical calculations; can be mechanical or electronic	an expert at calculation (or at operating calculating machines)
an expert at calculation (or at operating calculating machines)