Enter optimization inputs
The calculator uses a cost-minimization search with capacity, inventory, and service constraints.
Example Data Table
Use this sample set to test the calculator quickly. The Load Example Data button fills the same values into the form.
| Planning Days | Demand | Inventory | Supplier Cap | Warehouse Cap | MOQ | Step | Variable Unit Cost Inputs | Service Target |
|---|---|---|---|---|---|---|---|---|
| 30 | 12,000 | 2,500 | 11,000 | 10,000 | 1,000 | 500 | Sourcing 7.50, Production 9.25, Inbound 2.10, Outbound 3.40 | 97% |
Formula Used
- Daily Demand = Total Demand ÷ Planning Days
- Safety Stock Units = Total Demand × Safety Stock %
- Reserve Units = Total Demand × Reserve Factor %
- Target Requirement = Total Demand + Safety Stock Units + Reserve Units
- Feasible Max Order = minimum of Supplier Capacity and Warehouse Throughput Cap
- Effective Receipt = Order Quantity × (1 − Waste Rate %)
- Available Units = Current Inventory + Effective Receipt
- Fulfilled Demand = minimum of Available Units and Total Demand
- Service Level = Fulfilled Demand ÷ Total Demand × 100
- Shortage Units = maximum of (Target Requirement − Available Units) and 0
- Ending Inventory = maximum of (Available Units − Total Demand) and 0
- Variable Unit Cost = Sourcing + Production + Inbound Shipping + Outbound Shipping
- Expedite Units = Order Quantity × Expedite Share %
- Expedite Cost = Expedite Units × Expedite Premium
- Total Cost = Fixed Operating Cost + (Order Quantity × Variable Unit Cost) + Holding Cost + Shortage Penalty Cost + Expedite Cost
- Reorder Point = (Daily Demand × Lead Time Days) + Safety Stock Units
- Optimization Rule = test candidate order quantities, choose the lowest total cost that meets the service target, or the highest service result if no candidate reaches the target.
How to Use This Calculator
- Enter the planning horizon, expected demand, and current inventory.
- Add supplier capacity, warehouse throughput, and minimum order quantity.
- Set cost assumptions for sourcing, production, inbound, outbound, holding, and shortages.
- Choose safety stock, reserve factor, service target, and lead time.
- Enter expedite share and expedite premium if rush shipments are possible.
- Click Optimize Supply Chain to search candidate order quantities.
- Review the result cards, graph, and scenario table to understand the tradeoffs.
- Download the summary and tested scenarios as CSV or PDF for reporting.
FAQs
1. What does this calculator optimize?
It searches order quantities and compares total cost, service level, shortages, and ending inventory. The selected result is the least-cost scenario that reaches your service target whenever possible.
2. Why does the tool test many quantities?
A single closed-form answer rarely captures capacity limits, waste, expedite cost, and shortage penalties together. A scenario sweep lets you compare realistic order quantities under the same assumptions.
3. What is the difference between demand and target requirement?
Demand is expected customer need. Target requirement adds safety stock and reserve units, so the model can protect against volatility instead of planning only for the bare forecast.
4. When can the optimal order be zero?
Zero can be optimal when current inventory already covers demand and the service goal, or when ordering more increases cost without enough benefit. The model still tests that possibility.
5. What does shortage penalty represent?
It is the financial impact of not covering the target requirement. You can treat it as lost sales, emergency procurement, customer churn risk, or internal disruption cost.
6. How should I choose the search step?
Use smaller steps for better precision and larger steps for faster testing. For example, a 100-unit step is detailed, while a 500-unit step is useful for broad planning.
7. Can I use this for multi-site planning?
Yes, as a high-level model. Aggregate your network into combined demand, effective capacity, and average costs. For node-by-node routing, use a dedicated linear programming model.
8. What does the graph show?
The graph plots total cost across tested order quantities and overlays service level. It helps you see where cost bottoms out and whether extra quantity meaningfully improves fulfillment.