Column A is a list of months: 1/1/2009 thru 1/1/2015.
Column B has a corresponding interest rate based on user inputs.

There are 5 user inputs:

Rate: 5%
Rate Increase: 0.5%
Increase Date:6/1/09
Increase End Date: 10/1/09
Increase Frequency(months): 2

The formula would evaluate each row date against the user inputs and produce an interest rate in column B.

1/1/09 = 5.0%
2/1/09 = 5.0%
3/1/09 = 5.0%
4/1/09 = 5.0%
5/1/09 = 5.0%
6/1/09 = 5.5%
7/1/09 = 5.5%
8/1/09 = 6.0%
9/1/09 = 6.0%
10/1/09 and beyond = 6.0%

thanks in advance,

matt