The DATEVALUE function converts a date that is stored as text to a serial number that Excel recognizes as a date. For example, the formula =DATEVALUE ("1/1/2008") returns 39448, the serial number of the date 1/1/2008. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.