excel convert date number to date
So for dates before 03/01/1900, the Excel number is effectively the number of days after 12/31/1899. However, Excel will not format any number below 0 (-1 gives you ##########) and so this only matters for 01/00/1900 to 02/28/1900, making it easier to just use the 12/30/1899 date as a base.f you change the format of the cells to General then this will show the date value of a cell as behind the scenes Excel saves a date as the number of days since 01/01/1900. If your date is text and you need to convert it then DATEVALUE will do this: share | improve this answer. answered Nov 1 '13 at 8:05.