Inventory reorder-point scenario planner
Compare unreserved stock with lead-time demand and a chosen buffer.
Your inputs
Your results
Ready when you areYour results will appear here.
Compare two scenarios.
Run the tool, then save A or B to compare headline results and entered values. Keep currencies, periods and assumptions consistent.
Saved scenarios stay in this browser until you clear them. Reset clears the working result; it keeps saved scenarios. Use Clear saved scenarios on a shared device.
Run the tool to save your first scenario.
How it works
Add constant demand during replenishment lead time to the safety-stock buffer you choose. Compare the upward-rounded threshold with unreserved on-hand stock and model when that threshold would be reached.
A few things to know
No forecast, automatic orders or service-level promise. Excludes on-order receipts and demand variability. Zero demand has no time estimate. Stock counts must be whole units; inputs capped at one billion and unsafe thresholds rejected.
Results use your inputs. Keep all money amounts in the same currency.
When to use this tool
A reorder point is a threshold to compare with available stock under stated replenishment assumptions. Enter average daily demand, lead time and the buffer you choose. The planner rounds the threshold upward to a whole unit, subtracts reserved units from on-hand stock, and shows the constant-demand time until the threshold. Safety stock is an input here, not a statistical service-level calculation. Pending receipts, demand changes and supplier calendars can all change the operational decision, so use the result as a scenario rather than an automatically placed order.
- Compare stock with demand during a stated lead time.
- Test a different user-selected safety-stock buffer.
- Examine how reserved stock changes available units.
How to use inventory reorder-point scenario planner
Enter demand and lead time
Use average units per day and replenishment days on a consistent basis. Fractional demand and lead days are supported.
Declare whole stock counts
Enter safety-stock buffer, on-hand stock and reservations as whole units. Reservations cannot exceed on-hand stock.
Compare the threshold and time
Review the rounded threshold, available units and at-or-below status. Zero demand produces an unavailable time estimate; the model does not display infinite days as a recommendation.
A 100-unit replenishment threshold
Inputs
Daily demand 8, lead time 10 days, buffer 20, on hand 150, reserved 10.
Result
Threshold is 100 units. Available stock is 140. At constant demand, it reaches the threshold in 5 days.
What it means
The scenario excludes incoming stock and does not promise a supplier delivery date or service level.
Common mistakes to avoid
Counting reserved stock as available
Subtract reservations before comparing with the threshold.
Calling the selected buffer a calculated guarantee
The buffer is your assumption; demand distributions and service-level probabilities are not modeled.
Ignoring incoming orders
Pending receipts are deliberately excluded and may materially change an actual replenishment decision.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
How is the threshold calculated?
Multiply average daily demand by lead days, add the selected safety-stock units and round upward to a whole unit.
Why round upward?
The output is a whole-unit threshold. A small fractional requirement is rounded to the next whole unit rather than understating the modeled quantity.
What is available stock?
On-hand stock minus reservations. This does not include purchase orders, transfers or stock at another warehouse.
What does at or below mean?
The current available count is no greater than the threshold. The tool identifies that relationship; it does not submit a purchase order.
What happens with zero demand?
The threshold can still include your buffer, but time-to-threshold is unavailable. There is no division by zero or operational claim of infinite runway.
Are lead days business days?
Use your own consistent replenishment-day assumption. The calculator does not inspect supplier calendars, weekends, holidays or transport schedules.
Does this calculate safety stock statistically?
No. You choose a buffer. Variable demand distributions, service levels and seasonal forecasts are outside this scenario.
How is this different from inventory turnover?
Turnover describes a historical period’s inventory use. This compares stock with a prospective lead-time demand and buffer assumption.
Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.