If the current date/time settings represent dates in the format of Month/Day/Year, then the string, “1/8/2009”, would be converted to a datetime value equivalent to January 8th of 2009. However, if the current date and time settings represent dates in the format of Day/Month/Year, the same string would be converted as a datetime value equivalent to August 1st of 2009.
If the year portion of the date_text argument is omitted, the DATEVALUE function uses the current year from your computer’s built-in clock. Time information in the date_text argument is ignored.