Spare parts reorder point and safety stock

Safety stock and reorder point from usage and lead time.

Calculating…

How it's calculated

Safety stock = z × σ × √(lead time) Reorder point = usage × lead time + safety stock

Reorder when stock on hand falls to the reorder point. Service level is the chance of not running out during a lead time.

Critical, slow-moving spares (a gearbox or a specific drive) do not follow this demand-based model. Stock them based on criticality and downtime cost instead.