Date field referral

[senkurion]

Hi,

I have a date field called "Account Open On"in tabel as well as in query,
the same field also exists in report.

Now I want to calculate the interest rate in a text box based on that date
and the present date, I am using following expression in control source but
that is not working.

IIF(date()>=date[AccountOpenOn], [Initial Deposit]*[Interest
Rate]*0.01/Installement,0)
I am black walled here. Actually I wanted an expression which will
automatically calculate the interest rate every quarter the date "Account
Open On"

My date format is medium date

Thanks