How to use this calculator
Enter average daily sales, supplier lead time, safety stock, and current inventory.
The calculator tells you when inventory has reached the reorder threshold.
#998 · E-commerce Tool
Inventory Reorder Point Calculator
Calculate the reorder point, days until stockout, and order timing needed to avoid ecommerce inventory shortages.
Calculator
Inventory inputsunits/day
days
units
units
Ad space
What the result means
Reorder point is the inventory level where you should place a new purchase order to avoid stockouts during supplier lead time.
Reorder Point = Average Daily Sales × Lead Time + Safety Stock. Days Until Stockout = Current Inventory ÷ Average Daily Sales.
Update this calculation when demand, lead time, or supplier reliability changes.
Example calculation
With 18 units sold per day, 14-day lead time, and 120 safety stock, reorder point is 372 units.
Tips for better results
- Review fast-moving SKUs weekly.
- Add buffer for supplier delays.
- Use recent sales velocity, not stale averages.
- Separate reorder points by SKU.
FAQ
How do I calculate inventory reorder points?
Multiply average daily sales by supplier lead time, then add safety stock.
When should I reorder inventory?
Reorder when current inventory reaches or falls below the calculated reorder point.
What reorder point prevents stockouts?
A reorder point that includes realistic sales velocity, lead time, and safety stock helps prevent stockouts.
How much safety stock should I keep?
Safety stock should reflect demand variation, supplier delays, seasonality, and the cost of stockouts.
How does supplier lead time affect reorder points?
Longer lead time increases the reorder point because you need more inventory to cover sales while waiting for replenishment.
Related calculators
Inventory Reorder Point decision table
| Metric | Meaning |
|---|---|
| Reorder point | Inventory level that triggers a new order |
| Stockout days | Estimated days before inventory reaches zero |
| Safety stock | Buffer stock for demand or supplier uncertainty |
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