For the 2nd part you will need an If statement. Something like:
=if(day(a1)=16,eomonth(a1,0),date(year(a1),month(a 1)+1,16))

Regards,
Fred.

"GAIDEN" wrote in message
...
will this also help with the 2nd part of my question?

"JLatham" wrote:

Take a look at Excel Help for the EOMONTH() worksheet function. It is
part
of the Analysis ToolPak add-in in pre-2007 versions of Excel, so you may
need
to install that before the function is available to you.


"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