rate of inflation vs inflation rate

rate of inflation and inflation rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
rate of inflation	Yes	No	No	No
inflation rate	Yes	No	No	No

As nouns, rate of inflation and inflation rate are synonyms defined as:

rate of inflation and inflation rate: the rate of change of prices (as indicated by a price index) calculated on a monthly or annual basis

rate of inflation (noun)	inflation rate (noun)
the rate of change of prices (as indicated by a price index) calculated on a monthly or annual basis	the rate of change of prices (as indicated by a price index) calculated on a monthly or annual basis