Hi Gerardo,

See Chip Pearson at:

Dates And Times In Excel
http://www.cpearson.com/excel/datetime.htm#AddingDates

See particularly the section entitled:

How Excel Stores Dates And Times



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Regards.
Norman



"Gerardo" wrote in message
...
I'm trying to work with graphs and dates, in my code I'm using Datediff to
get the serial number for a given date and then graph the value. The
problem
is that the difference between 04/01/2008 (mm/dd/yyyy) and 01/01/1900 is
giving the serial number of 2 days earlier. I know that I should add one
to
get the serial number for April 1st 2008, instead I'm getting the serial
number for March 31st 2008.

Isn't this odd?