Inventory Reorder Point Calculator
At what inventory position does my demand and lead-time arithmetic indicate reordering? Check the formula, a worked example and the stated measurement limits.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Average daily demand (units/day) | Enter average daily demand in units/day. Use the measurement basis described below. |
| Lead time (days) | Enter lead time in days. Use the measurement basis described below. |
| User-chosen safety stock (units) | Enter a whole count in units; keep the reporting population consistent. |
Understanding your result
Use the threshold as a deterministic planning reference. Investigate stockouts, order multiples and lead-time variability before applying it operationally.
Common mistakes
- Working-day demand with calendar-day lead time mixes bases.
- On-hand quantity alone can omit stock already ordered or committed.
- Mixing annual and monthly periods, or leaving out a cost that the model does not include.
Check your calculation
- Compare a simple one-period or zero-change case with hand arithmetic before applying a longer scenario.
Choose a consistent measurement basis
Use demand and lead time from a comparable SKU, supplier and calendar convention. A reorder decision usually uses inventory position: on-hand plus on-order minus committed or backordered demand.
A second independently worked case
Zero average demand leaves only the entered reserve in this simplified threshold. Inputs: Average daily demand: 0 units/day; Lead time: 10 days; User-chosen safety stock: 30 units. Results: Rounded reorder point: 30 units; Expected lead-time demand: 0 units.
Precision and output units
Displayed results: Rounded reorder point in units, rounded to 0 decimal places; Expected lead-time demand in units, rounded to 3 decimal places. Display rounding does not establish the precision of the original measurements or estimates.
Calculation checks, sources and review limits
At what inventory position does my demand and lead-time arithmetic indicate reordering?
At what inventory position does my demand and lead-time arithmetic indicate reordering? Check the formula, a worked example and the stated measurement limits.
Common uses
- At what inventory position does my demand and lead-time arithmetic indicate reordering
- Compare Inventory Reorder Point across scenarios under matching definitions.
How it works
Multiply average demand per day by lead time in matching days, add the safety stock chosen by the user, and round upward to a whole unit.
Worked example
12 × 10 = 120 expected lead-time demand; plus 30 reserve gives 150 units. Enter average daily demand 12 units/day, lead time 10 days, user-chosen safety stock 30 units. The independently worked result is rounded reorder point 150 units; expected lead-time demand 120 units. Compare this example with your reporting definitions before substituting your own figures.
FAQ
How is inventory position different from stock on hand?
Inventory position can include on-order stock and subtract committed or backordered demand. For example, 100 on hand plus 50 ordered minus 30 committed gives a position of 120.
Does the entered safety stock establish a service level?
No. Safety stock is a user-chosen quantity here. The calculator does not infer a probability distribution, uncertainty buffer or stock-availability guarantee.