The basic reorder calculation
Reorder point = average daily unit sales × replenishment lead time in days + safety stock in units. If sales average 8 units a day, lead time is 35 days and you want 10 extra days of cover, safety stock is 80 units and the reorder point is 360 units.
Estimate days of cover and the gap
Days of cover = usable stock ÷ average daily sales. At 200 units and 8 sales a day, you have 25 days of cover. A 35-day lead time creates an estimated 10-day gap before replenishment if no incoming shipment arrives in time. These are planning estimates; changing sales can move the dates.
Include the full replenishment journey
Lead time should cover production, preparation, freight and the time until stock is actually available for sale. Incoming stock helps only if it becomes sellable before the shortage. Avoid counting the same shipment as both on-hand inventory and incoming units.
Decide quantity and cash together
A reorder trigger is different from the quantity to buy. Quantity also depends on desired coverage, minimum order size and usable incoming stock. Multiply suggested units by the relevant purchase cost and include extra freight or setup cash where applicable. Revisit sales pace after promotions or a stockout; the tool uses manual inputs and does not monitor marketplaces or send alerts.