SAFETY STOCK CALCULATOR

Safety Stock Lab

Model the inventory required to protect service under demand variability, lead-time variability, or both.

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Result

Deterministic answer with practical interpretation.

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Your result will appear here.

Enter the assumptions, then calculate to see the answer, interpretation and next check.

Methodology, assumptions and limitations

SS = z × √(L × σd² + d̄² × σL²)

z is the cycle-service z-score; σd is demand standard deviation per period; L is mean lead time; σL is lead-time standard deviation.

Assumptions

Demand and lead-time units must use compatible periods.
Method C assumes demand and lead-time variability are independent.
The normal approximation may be weak for intermittent, skewed, or promotion-driven demand.
Cycle service level is not the same as fill rate.