On Tue, 21 Oct 2008 11:17:18 -0700, gcw wrote:

If you enter DATE(2008,10,1) as the Start_date and 10/1/08 as the End_date it
shows a difference of N=1 workday. Which means the system is subtracting
39722 from 39722 and getting a total of 1.

If you enter DATE(2008,11,1 ) as the Start_date and 11/1/08 as the End_date
it shows a difference of N=0 workdays. Which means the system is correctly
subtracting 39753 from 39753 and getting a total of 0.

What is causing the difference when the same formula is used? Is this a
glitch in the system?

No glitch.

NETWORKDAYS returns the number of whole working days between start_date and
end_date.

In this case, the word "between" is used in an INCLUSIVE sense and includes the
first and last days.

Your first formula returns a 1, because you have "1" working day (1 Oct 2008)

Your second formula returns a "0" because 1 Nov 2008 is a Saturday, which is
not counted as a work day by this function.
--ron