Business Object Calculator Time Function

=If(FormatDate([End date]; "dd-MM-yyyy") <> "")
Then ((DaysBetween([Start date];[End date])*24*60)+
((ToNumber(FormatDate([End date];"HH"))*60)-(ToNumber(FormatDate([Start date];"HH"))*60))+
(ToNumber(FormatDate([End date];"mm"))-(ToNumber(FormatDate([Start date];"mm"))))+
((ToNumber(FormatDate([End date];"ss"))/60)-((ToNumber(FormatDate([Start date];"ss"))/60))))
/60 Else "0"