the first line is materials available at the begining of the month, in transit is materials ordered and on the way, PO is the material purchased, Requirement is what is needed to fufil the order demand for the next month. demand is custormer order, ending inventory is what is left, days of stock is how long the inventory will last in the following month. i am trying to come up with an excel code or formula so that the requirement tab will always update itself on what is needed so the days of stock is within 25 - 30 days.

C B D A G E F H 1 Jul Sep Jun Oct Nov Dec 2 Aug 10924 7770 5631 4312 556 3656 8091 20 0 4879 0 0 0 0 21 ole 3820 5200 0 0 0 0 22 23 22012788 4.5 LSO LTC API 10th In Transit PO's Requirement Demand Ending Inventory Days of Stock +2367 3154 4264 2139 1319 3756 3969 24 10924 8091 7770 5631 4312 556 (3413) 25 26 117 120 111 47 4 79 26 C B D A G E F H 1 Jul Sep Jun Oct Nov Dec 2 Aug 10924 7770 5631 4312 556 3656 8091 20 0 4879 0 0 0 0 21 ole 3820 5200 0 0 0 0 22 23 22012788 4.5 LSO LTC API 10th In Transit PO's Requirement Demand Ending Inventory Days of Stock +2367 3154 4264 2139 1319 3756 3969 24 10924 8091 7770 5631 4312 556 (3413) 25 26 117 120 111 47 4 79 26