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Safety Stock Calculator
Calculate how much buffer inventory (safety stock) you need to avoid running out of stock during unexpected demand or supply delays.
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days
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days
What is safety stock?
Safety stock is extra inventory a business keeps on hand as a buffer against uncertainty in demand or supplier lead time, helping avoid stockouts.
The formula
Safety Stock = (Maximum Daily Usage × Maximum Lead Time) − (Average Daily Usage × Average Lead Time). This classic formula compares a worst-case scenario against the average case to size an appropriate buffer.
This calculator is for general inventory-planning education; real-world safety stock models may also factor in service-level targets and demand variability statistically.
Last reviewed August 2026