The Stock-Out Sentinel

Calculate your probability of stock-out using real-world variance. No spreadsheets. No guesswork. Just the math that keeps the lights on.
Field Inputs
120
7
18
95%
The Verdict
Probability of Stock-Out
5.0%
SAFE TO RUN
Recommended Safety Stock: 245 units
Logic:
SS = Z × σ × √LT
Where Z is the standard normal deviate for your target service level.
Stock-Out Prob = 1 - Service Level
Dark warehouse aisle with stacked inventory
Aisle 4, Dover Distribution Center. November 2025. We missed $40k here because we trusted a forecast, not the variance.