Is there a formula that can calculate future monthly and semi monthly due
dates correctly.

If you are looking to find the last day of a month try
=DATE(YEAR(A1),MONTH(A1)+1,1)-1

To find the next semimonth due date
=DATE(YEAR(A1),IF(DAY(A1)<16,MONTH(A1),MONTH(A1)+1 ),16)


Example: 05-31-2009 + ???? = 06-30-2009 + ???? = 07-31-2009

Example: 05-16-2009 + ???? = 05-31-2009 + ???? = 06-16-2009 + ???? =
06-30-2009

Try DATEDIF()

A1 = 05-31-2009
B1 = DATEDIF(A1,C1,"d")
C1 = 06-30-2009
D1 = DATEDIF(C1,E1,"d")
E1 = 07-31-2009

If this post helps click Yes
---------------
Jacob Skaria


"GAIDEN" wrote:

Is there a formula that can calculate future monthly and semi monthly due
dates correctly.

Example: 05-31-2009 + ???? = 06-30-2009 + ???? = 07-31-2009

Example: 05-16-2009 + ???? = 05-31-2009 + ???? = 06-16-2009 + ???? =
06-30-2009