Safety-Stock & Service-Level Cost Optimizer

Size the order quantity, safety stock and reorder point for an item with uncertain demand, see what each service level costs, and find the service level that minimizes total cost. Runs entirely in your browser.

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1. Demand and lead time

Mean demand per period (units)

Std deviation of demand per period (units)

Lead time (periods, same unit as demand)

Periods per year

2. Costs and policy

Order cost ($ per order)

Holding cost ($ per unit per year)

Order quantity (optional; blank = EOQ)

Target cycle service level (%)

Cost per unit short ($) (optional; shortages backordered)

When NOT to use this

Demand over the lead time should be roughly normal and the lead time constant. Lumpy, intermittent or heavily skewed demand, and variable lead times, are outside this version.
It models a continuous-review (Q, R) policy only, not periodic review or min/max systems. Shortages are assumed backordered, not lost.
No quantity discounts or seasonality. Holding cost is a single number you supply.
The cost per unit short is the weakest input. The full cost table shows the range where the answer barely changes.
It is not a forecast. A poor estimate of demand variability gives a poor safety stock.
Fill rate and cycle service level are different measures; the table shows both.