orderstorlek

Orderstorlek, a Swedish term often used in inventory management, refers to the quantity of units ordered in a single replenishment. It is a central decision variable in procurement and stock control, influencing both inventory holdings and ordering frequency as well as service levels.

In classical inventory theory, the optimal orderstorlek minimizes the total cost of inventory, which consists of ordering costs and holding costs. The Economic Order Quantity (EOQ) model expresses this balance as EOQ = sqrt(2DS/H), where D is the annual demand, S is the fixed cost per order, and H is the annual holding cost per unit. The idea is to order enough to satisfy demand until the next replenishment while keeping average inventory low. The model assumes constant demand, fixed lead times, and no quantity discounts, and is often extended with safety stock to account for variability.

Practical considerations include supplier constraints (minimum order quantities and packaging sizes), transportation costs, storage capacity, and lead times. Many real-world scenarios also involve quantity discounts, which can change the optimal orderstorlek by creating stepwise improvements at certain purchase thresholds. In addition, demand variability, service level targets, and risk of stockouts may lead to using periodic review strategies or maintaining safety stock alongside the base EOQ.

Example: with annual demand D = 10,000 units, ordering cost S = 50 per order, and holding cost H = 2 per unit per year, the EOQ is about 707 units. This leads to roughly 14 orders per year and a balanced trade-off between ordering and holding costs.