Stuck trying to figure out how to insert a calculated column... below is my code but it's only returning the values that already exist in the column May16
Column = CALCULATE(SUM(Sheet1[May16]),FILTER(ALL(Sheet1[Day of Month]),Sheet1[Day of Month]<= MAX (Sheet1[Day of Month])))
Day of Month is just a column with the day of the month number so May 31st = 31