I have a large worksheet that contains dates in one column. I need all dates to be the last day of the month. Example: if the date is 5/26/2010 I need for it to be 5/31/2010, if 2/05/2008 S/B 2/28/2008. I am doing it by sorting and changing now. The list is growing to over 50,000 lines. Any help would be appreciated.