Reorder Point

Reorder point (ROP) is the inventory level that triggers replenishment so stock arrives before depletion. It is commonly calculated as lead-time demand plus safety stock, where lead-time demand equals average daily usage or forecast demand multiplied by supplier lead time. When on-hand inventory reaches ROP, an ERP/WMS flags a purchase order or replenishment activity.

On the shop floor or in a warehouse, the reorder point is configured for each SKU, component, or raw material line so the ERP or WMS automatically flags or creates a purchase order when on-hand inventory falls to that threshold. For manufacturing, the useful interpretation is not simply 'reorder when low' but 'reorder when remaining inventory equals the expected consumption during replenishment lead time.' This prevents line stoppage while the next lot is in transit or being received. ROP is typically applied to independent-demand items such as fasteners, resin, packaging, MRO spares, and bought-in subcomponents, where consumption is measured from issue or pick transactions. Operationally, ROP supports pull-based replenishment: a bin count, cycle count, or system decrement crosses the threshold, and the planner reviews order quantity, supplier MOQ, and receipt timing before inventory reaches zero. This keeps production running smoothly and avoids carrying excess stock.

• ⚠️Stockouts despite a reorder point: An unchanged lead time in the calculation while supplier performance stretches triggers orders too late, so material hits zero before shipment arrives, especially on imported or congested lanes.
• ⚠️Excess inventory and cluttered staging: Setting safety stock too high, or omitting it entirely, causes either early reordering that inflates carrying cost or empty bins during demand spikes and scrap. The result is uneven material flow and wasted space.
• ⚠️Late or missing replenishment triggers: Inaccurate issue transactions, backflushes, scrap postings, or cycle counts make on-hand seem higher than reality, so ROP fires late or not at all. One missing part can stop an entire work center.