Count / Calculate Days between Two Dates: =DATEDIF(A1,A2,"D")
Count / Calculate Months between Two Dates: =DATEDIF(A1,A2,"M")
Count / Calculate Years between Two Dates: =DATEDIF(A1,A2,"Y")
Count / Calculate Years Months and Days between Two Dates: =DATEDIF(A1,A2,"Y") & " Years, " & DATEDIF(A1,A2,"YM") & " Months, " & DATEDIF(A1,A2,"MD") & " Days"