“The interest rate on/of/for my savings account is 3 %.” Which preposition is correct? Thanks.

“Of” sounds most correct here, but “on” or “for” would be understood. Personally I would rephrase the sentence and say “My savings account has a 3% interest rate.”

All three would be understood, I use and have heard "on" much more frequently that the others.

"on" is the usual choice.

I would use "of". All of them sound fine though.

On