Reorder Quantity
Definition
The number of units ordered when a replenishment is triggered. It may be a fixed lot size such as the EOQ, or a variable amount calculated to reach a target stock level.
In Practice
Reorder quantity answers the second half of the replenishment question: the reorder point says when, the reorder quantity says how much. In continuous review systems it is usually fixed, often anchored on the EOQ and then adjusted for pack sizes, pallet quantities, supplier minimums, and price breaks. In periodic and min-max systems it varies, calculated as target level minus current inventory position.
Practical constraints usually dominate the pure math. A theoretically optimal 730 units becomes 720 to fill 30 cases of 24, or jumps to 1,000 to reach a freight break. The planner's job is knowing what each rounding decision costs in holding or ordering expense so constraints are accepted consciously.
Example: EOQ suggests ordering 850 units of a cleaning chemical, but the supplier ships full drums of 200. The buyer sets the reorder quantity to 800, four drums, accepting a cost penalty of under 1 percent versus the unconstrained optimum.
Related Calculators
Related Terms
The inventory level that triggers a replenishment order. It equals expected demand during supplier lead time plus safety stock.
Economic Order QuantityThe order size that minimizes the combined cost of ordering and holding inventory. EOQ balances the fixed cost of placing orders against the cost of carrying stock.
ReplenishmentThe process of restocking inventory to meet ongoing demand, whether by purchasing from suppliers, transferring between locations, or triggering production. It is the execution engine that keeps stock policies real.
Min-Max PlanningA simple replenishment method where an order is triggered when inventory falls to a minimum level and stock is replenished up to a maximum level. The min acts as the reorder point and the max caps the order-up-to quantity.