Required Safety Stock
115
Service level and inventory capital
Protect your SLA without overstocking.
Set the service level your customers expect and see the Safety Stock — and capital — required to support it.
Calculate Safety Stock from your chosen service level, demand variability and lead time — then see the cost of moving to a higher SLA.
You don't need to know the standard deviation. Enter the usual range of demand and lead time — the calculator does the statistical work.
Demand and supply inputs
Inventory required for your SLA
Indicative capital in Safety Stock
€2,875
Indicative reorder point
1,115
At 95% SLA, the model recommends about 115 units of Safety Stock, tying up approximately €2,875. Moving the target changes the protection level and the capital requirement immediately.
This is a planning estimate based on normally distributed demand and independent demand and lead-time variability. Validate critical items against actual stockout history and supplier performance.
How is this calculated?
From your usual range we estimate the fluctuation as (max − min) / 6, assuming the usual range covers about ±3 standard deviations. Safety Stock = Z × √(lead time × demand fluctuation² + average demand² × lead-time fluctuation²), where Z comes from your target service level.
Estimated fluctuation used: 6.67 units / day of demand and 0.67 days of lead time.
The capital trade-off across SLA levels
| SLA | Safety Stock | Capital |
|---|---|---|
| 90% | 90 | €2,241 |
| 95% | 115 | €2,875 |
| 97% | 132 | €3,288 |
| 98% | 144 | €3,590 |
| 99% | 163 | €4,066 |
| 99.5% | 180 | €4,503 |
Protect your SLA without overstocking.
Calculate Safety Stock from your chosen service level, demand variability and lead time — then see the cost of moving to a higher SLA.