Returns the serial number of the current date. The serial number is the date-time code used by Microsoft Excel for date and time calculations. If the cell format was General before the function was entered, the result is formatted as a date.
Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Microsoft Excel for the Macintosh uses a different date system as its default.