The start date is in cell D1, and the end date is in E1:[FONT=Segoe UI, Segoe UI Web, Segoe UI Symbol, Helvetica Neue, BBAlpha Sans, S60 Sans, Arial, sans-serif]
=[/FONT]DATEDIF[FONT=Segoe UI, Segoe UI Web, Segoe UI Symbol, Helvetica Neue, BBAlpha Sans, S60 Sans, Arial, sans-serif](D1,E1,"m")[/FONT]