Reorder Point Calculator
Find when to reorder inventory.
The reorder point triggers a new order before you run out.
How the Math Works
The Reorder Point (ROP) formula calculates when inventory should be replenished to prevent stockouts. It multiplies your average daily usage by the supplier lead time (days until delivery arrives) and adds safety stock - extra inventory kept as a buffer against demand fluctuations or delivery delays. For example, if you sell 20 units per day, your supplier takes 5 days to deliver, and you keep 30 units as safety stock, your reorder point would be 20 × 5 + 30 = 130 units.
Practical Applications
To use this calculation practically, first determine your average daily consumption by dividing total units sold or used over a period by the number of days. Measure your supplier's lead time from order placement to delivery receipt. Calculate safety stock based on demand variability - typically 1-2 days of usage for stable products, or more for seasonal items. When your inventory drops to or below your ROP, place a new order immediately to maintain continuous availability.
Day-to-Day Use
This calculation prevents the stress of running out of essential items while traveling, ensures your favorite products stay in stock at home, and helps small businesses avoid lost sales from empty shelves. Whether you're managing office supplies, ordering groceries, or planning vacation rentals, knowing exactly when to reorder saves money, reduces frantic last-minute purchases, and eliminates the anxiety of wondering 'is it time to buy more yet?'
Worked example
50/day × 7 days + 100 → 450 units.
FAQ
Safety stock?
Buffer for demand spikes and supply delays.