Chemical Inventory Manager Calculator

This calculator tracks chemical inventory value and reorder timing from current stock levels, average unit cost, monthly consumption, supplier lead time, and shelf life. Total inventory value is a straight product of current stock units and average cost per unit -- the number of distinct chemical products in inventory (numChemicals) does not enter that calculation at all, since total value only tracks total units on hand, not how many different chemicals make up that total. The reorder point combines expected demand during supplier lead time with a safety stock buffer, so the calculator flags when current stock dips below what is needed to cover the gap until the next delivery arrives.

It also estimates waste risk from expiration: if the current stock represents more months of supply than the average shelf life covers, the excess is flagged as at risk of expiring unused, valued at the average unit cost. Economic order quantity (EOQ) uses the standard EOQ model -- balancing a fixed per-order cost against a holding cost estimated at 25% of unit cost annually -- to suggest an order size that minimizes total ordering-plus-holding cost. This model averages unit cost, shelf life, and usage rate across the whole inventory rather than tracking each chemical individually, so a lab with a few very expensive reagents and many inexpensive solvents will see less precise reorder and waste-risk figures than a lab with a more uniform chemical mix; real inventory management still requires per-chemical tracking for accurate reorder timing and hazard-class-specific storage limits.