Reference desk
MRO Inventory Formulas
Formula outputs support a policy decision; criticality, intermittency, and supply recovery still require engineering judgment.
| Metric | Formula | Decision use |
|---|---|---|
| Lead-time demand | Average daily demand × lead time | Expected replenishment exposure. |
| Reorder point | Lead-time demand + safety stock | Replenishment trigger. |
| Safety stock | z × demand standard deviation × √lead time | Normal-demand uncertainty buffer. |
| EOQ | √(2DS ÷ H) | Order/carrying cost balance. |
| Turnover | Annual issues ÷ average inventory | Movement of inventory value. |
Use formulas within a policy
Check shelf life, preservation, criticality, substitution, minimum order quantities, and supplier failure risk before changing stocked quantities. Low movement can be correct for insurance spares.
Related tools
Lead-time demand, EOQ, inventory turnover, and MRO safety stock guide.