1) How to calculate memberId? based on contact numbers... open new sheet past contact no into B column and right it down the formula into A column 2nd row =IF(B1=B2, A1+1, A1) ---------------------------------------------------------------------------------------------------------------------------- 2) How to calculate End date using start date and duration? open second sheet past start date in A1 and Second column B2 past duration memberships =DATE(YEAR(A2),MONTH(A2)+B2,DAY(A2)) note:-