Calculator (Inputs)
Results (Safety Stock / Reorder Point)
Safety Stock & Reorder Point Calculator
Estimate safety stock and reorder point based on demand and lead time variability.
Also known as safety stock calculator / reorder point calculator.
Calculator (Inputs)
Use the same unit for demand and lead time.
Demand and lead time units differ; we converted units to calculate
Demand (mean + variability)
Demand variability (rough is ok)Estimated as ~95% typical range
Use if you have historical data
CV = standard deviation / mean. Medium is a safe default.
Lead time (mean + variability)
Lead time variability (rough is ok)Average time from order to arrival
Estimated as ~95% typical range
Use if you have historical data
CV = standard deviation / mean. Medium is a safe default.
Target service level
Service level here is the probability of not stocking out during lead time (approx.).
उन्नत
Seasonality (period-by-period)
Split into periods and calculate safety stock/ROP for each.
राउंडिंग
e.g. box=1, bundle=5, roll=1 (defaults to 1)
Safety stock
We estimate safety stock and reorder point with these simplified formulas:
मान्यताएं
- Demand and lead time variability are independent (simplified)
- Normal distribution approximation (simplified)
- Results are guidelines (MOQ, order units, and storage limits are separate)
Common formulas
σ_DL = √( μ_L × σ_D^2 + μ_D^2 × σ_L^2 )
Safety stock SS = z × σ_DL
Reorder point ROP = ( μ_D × μ_L ) + SS
Reorder point
प्रतीक
- Mean demand: μ_D (units/day or units/week)
- Demand standard deviation: σ_D
- Mean lead time: μ_L (days or weeks)
- Lead time standard deviation: σ_L
- Service level z value: z
Service level → z (approx.)
- Low: 90% → z ≒ 1.28
- Medium: 95% → z ≒ 1.65
- High: 98% → z ≒ 2.05
Lead time variability
If estimating from min/max
Estimate σ ≒ (max − min) ÷ 4 (assumes ~95% typical range)
- 90% (±1.645σ): divisor ≒ 3.29
- 95% (±1.96σ): divisor ≒ 3.92
- Almost all (±3σ): divisor ≒ 6
If variability is unknown
- Min/Max is a practical starting point
- If you have data, compute mean and standard deviation from recent history
- Default service level: Medium (95%)
सामान्य प्रश्न
Use min/max estimation. Treat the usual range as ~95% and we estimate σ automatically. It's often good enough to start.
It's a target for avoiding stockouts during lead time. Higher service levels reduce stockouts but increase safety stock.
Split by period and compute safety stock/ROP for each season. Switching reorder points by period is usually easiest operationally.
This tool estimates when to order. Order quantity depends on MOQ, order units, storage capacity, costs, and policy.
नोट्स
- This tool is for calculation support and does not replace design, legal, contract, or safety requirements.
- Presets are examples only and may vary by situation.
- Results are guidelines. Consider MOQ, order units, storage, budget, and disposal risk separately.
- For highly intermittent demand or unstable supply, adjust based on actual performance.