Raw Materials Holding Period=
Average Inventory of Raw Materials/Annual Usage (purchases) x365
Average Production Period=
Average Inventory of WIP/Annual Cost of Sales x 365
Average Holding Period=
Average Inventory of Finished Goods/Annual Cost of Sales x 365
Average Receivables Days=
Average Receivables/Annual Sales Revenue x 365
Average Payable Payment Period=
Average payables/Average Purchases (or Cost of Sales) x365