installment rate vs payment rate

installment rate and payment rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
installment rate	Yes	No	No	No
payment rate	Yes	No	No	No

As nouns, installment rate and payment rate are synonyms defined as:

installment rate and payment rate: the amount of money paid out per unit time

Other synonyms of installment rate include rate of payment, repayment rate.

installment rate (noun)	payment rate (noun)
the amount of money paid out per unit time	the amount of money paid out per unit time