The formula for daily compounded interest usually looks like this:

V = D(1 + r/365)³⁶⁵ⁿ

D is the principal
r is the interest rate
n is the number of years
V is the final amount

Will that do? If not, can you describe the task a bit more?

I do not have an example db for you, however it could be built fairly simply.  You would need to create a form with a total of 5 fields.  2 date fields to enter the range of dates the money will earn interest, a field to enter the interest rate, a field to enter the principal amount, and a field to have the new balance show up in.  The code to then calculate the compounded interest would then look something like this:


var vTo as Int
var vFrom as Int
var vDays as Int

     vTo = @ToNumber(ToDate)
     vFrom = @ToNumber(FromDate)      
     If vTo >= vFrom
     {
           vDays = (vTo - vFrom)
           //the below line assumes that the interest rate is inserted as a percent and not a decimal
           TotBalance = Principal * (@EXP(1 + InterestRate / 36500, vDays))
     }
     Else
     {
           @MsgBox("The date the principal stops earning interest cannot be earlier than when it begins earning interest.")
     }