Calculator Inputs
Example Data Table
| Stage or Metric | Example Value | Notes |
|---|---|---|
| Order Processing | 2 days | Internal approval and purchase order release. |
| Supplier Queue | 3 days | Waiting before production begins. |
| Production | 7 days | Manufacturing or order preparation time. |
| Export Customs | 2 days | Documentation and outbound clearance. |
| Transit | 10 days | Main transport movement. |
| Import Customs | 3 days | Inbound release and inspection time. |
| Local Delivery + Receiving | 3 days | Last-mile delivery and warehouse intake. |
| Calculated Total Lead Time | 32.67 days | Includes variability adjustment and safety buffer. |
Formula Used
Base Lead Time = Order Processing + Supplier Queue + Production + Export Customs + Transit + Import Customs + Local Delivery + Receiving
Risk Adjustment = Base Lead Time × (Variability % ÷ 100) × (Service Factor ÷ 2)
Total Lead Time = Base Lead Time + Safety Buffer + Risk Adjustment
Planning Horizon = Total Lead Time + Review Cycle Days
Pipeline Inventory = Average Daily Demand × Total Lead Time
Reorder Point = Average Daily Demand × Planning Horizon
Service factor converts the selected service level into a risk weight. Higher service targets create larger protective time allowances.
How to Use This Calculator
- Enter the expected days for each operational stage.
- Add a safety buffer for planned protection time.
- Estimate lead time variability as a percentage.
- Choose the target service level for planning conservatism.
- Provide review cycle days and average daily demand.
- Press the calculate button to display results above the form.
- Use planning horizon and reorder point for replenishment policies.
- Download CSV or PDF results for reporting or handoff.
FAQs
1. What does lead time mean here?
It is the total elapsed time from placing an order to receiving stock into inventory. The calculator breaks that timeline into operational stages for better planning insight.
2. Why include variability percentage?
Variability reflects uncertainty from congestion, supplier delays, inspections, or transport disruption. Adding it helps you plan with realistic protection instead of relying only on ideal timings.
3. What is the safety buffer used for?
Safety buffer is a fixed extra allowance you choose manually. It covers known risks, seasonal pressure, or internal review delays that are not fully captured by variability percentage alone.
4. How is service level applied?
The chosen service level maps to a service factor. Higher targets increase the risk adjustment, which raises total lead time and reorder planning to protect customer fill rates.
5. What is planning horizon?
Planning horizon adds review cycle days to total lead time. It shows how long demand must be covered before the next replenishment decision can safely arrive.
6. What does reorder point represent?
Reorder point estimates the inventory level where a new order should be triggered. It is based on daily demand multiplied by the planning horizon.
7. Can I use hours instead of days?
Yes, if every input uses the same unit consistently. Rename the labels in your deployment if you want an hourly version for shorter cycle environments.
8. Who can use this calculator?
It fits buyers, supply planners, import teams, warehouse managers, and operations analysts. Anyone managing replenishment timing can use it to evaluate delays and stocking impact.