overestimate vs overrating

overestimate and overrating both are nouns.

Word	Noun	Adjective	Verb	Adverb
overestimate	Yes	No	Yes	No
overrating	Yes	No	No	No

As nouns, overestimate and overrating are synonyms defined as:

overestimate and overrating: a calculation that results in an estimate that is too high

Other synonyms of overestimate include overestimation, overreckoning.

overestimate (noun)	overrating (noun)
a calculation that results in an estimate that is too high	a calculation that results in an estimate that is too high
an appraisal that is too high

overestimate (verb)	overrating (verb)
make too high an estimate of
assign too high a value to