A working planner's scratchpad: plug in your numbers, copy the safety stock and reorder point straight into the KPI Excel template or the SOP pack from the Cratepost shop.
Inputs
Plug in the three numbers.
Safety Stock = Z × D̄ × √L — treating demand variability as proportional to the square root of average daily demand. A common practitioner shortcut when only the average and lead time are on hand.
Units sold or consumed per day.
Days from PO to receipt. Minimum 0.5.
1.65 ≈ 95%, 2.33 ≈ 99%.
Defaults: 50 u/day · 7 d · z 1.65.
Recommended buffer
Safety stock at z = 1.7 (95% service level) for 50 u/day over 7 d.
218.3units
Recommended buffer for the inputs above. Reorder when on-hand drops to 568.3 units.
Avg daily demand
50 u/day
Lead time
7 days
z-score
1.7 σ
Safety stock
218.3 units
Reorder point
568.3 units
Demand profile
How the four numbers stack up.
Daily demand, demand during lead time, the safety-stock buffer, and the reorder point that pulls the trigger.