How to use this calculator
Enter current units, average daily sales, supplier lead time, and safety stock. The calculator shows when inventory falls below the reorder point.
#1012 · E-commerce Tool
Amazon Reorder Calculator
Find the right Amazon reorder point using current inventory, daily sales, supplier lead time, and safety stock so you can avoid FBA stockouts and excess inventory.
Calculator
Decision inputsunits
/day
days
units
Ad space
What the result means
If current inventory is near or below the reorder point, a replenishment order is urgent. Healthy coverage gives enough time for supplier and inbound delays.
Reorder point = Daily sales × Supplier lead time + Safety stock. Days left = Current inventory ÷ Daily sales.
Adjust daily sales for seasonality, ad campaigns, Prime Day, and supplier reliability.
Example calculation
With 800 units, 25 sales per day, 18 days lead time, and 100 safety stock, reorder point is 550 units and coverage is 32 days.
Tips for better results
- Use the last 30 to 90 days of sales, not a single spike.
- Add more safety stock for overseas suppliers.
- Recheck reorder timing before promotions.
FAQ
When should I reorder Amazon inventory?
Reorder when inventory approaches daily sales multiplied by lead time plus safety stock.
How much safety stock should Amazon sellers keep?
Many sellers keep 7 to 14 days of sales as safety stock, but volatile demand may require more.
What is a good reorder point for FBA?
A good reorder point covers supplier lead time, inbound shipping, receiving delays, and a safety buffer.
How do I avoid Amazon stockouts?
Track days of inventory, reorder point, supplier lead time, and seasonal sales changes before inventory becomes urgent.
How many inventory days are ideal for Amazon sellers?
Many sellers aim for 30 to 60 days, balancing stockout protection with storage cost and cash flow.
Related calculators
Decision module
| Metric | Use |
|---|---|
| Reorder point | Minimum inventory level before placing another order. |
| Coverage days | Estimated number of days before inventory runs out. |
| Risk status | Flags urgent reorder or overstock risk. |
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