You can use the two formulas below that should be entered into a blank cell where you can get the result. In this case, to be able to determine the number of days between cell B10 (9/1/2014) and the current date, then;
=IF(OR(C10="",B10=""),"",INT(C10-B10+1))=IF(NOT(OR(ISBLANK(C10),ISBLANK(B10))),C10-B10+1,"")