Reorder Point Calculator
Determine exactly when to reorder inventory so you never run out of stock or tie up capital in excess inventory.
Your Inputs
Enter your usage and lead time parameters below.
Results
Enter your inputs and click Calculate to see results.
Results will appear here after you calculate.
What is a Reorder Point?
A reorder point (ROP) is the inventory level at which a new purchase order should be placed to replenish stock before it runs out. It accounts for both your average consumption rate and the time it takes for new stock to arrive, plus a safety buffer to handle demand spikes or supplier delays.
The Reorder Point Formula
The reorder point formula is ROP = (Avg Daily Usage × Lead Time) + Safety Stock, where safety stock is calculated as (Max Daily Usage - Avg Daily Usage) × Lead Time. This approach uses your worst-case demand scenario to determine how much buffer inventory you need.
- Max Daily Usage — The highest number of units you sell or consume in a single day. This represents your peak demand scenario.
- Average Daily Usage — The typical number of units sold or consumed per day, averaged over a representative period.
- Lead Time — The number of days between placing a purchase order and receiving the goods into your warehouse.
Reorder Point vs Safety Stock
Safety stock and reorder point are related but distinct concepts. Safety stock is the extra inventory held as a buffer against uncertainty — it protects you when demand exceeds your average or when suppliers deliver late. The reorder point, on the other hand, is the trigger level that tells you when to place a new order. Your reorder point includes both the inventory you expect to sell during lead time and your safety stock cushion.
How Nventory Helps
Nventory continuously monitors your stock levels across every sales channel and warehouse. When inventory for any SKU drops to its reorder point, Nventory automatically sends alerts and can even generate draft purchase orders — so you never miss a reorder window. With real-time demand tracking and supplier lead time analytics, your reorder points stay accurate as your business evolves.
Want automated reorder alerts and real-time inventory monitoring?
Frequently Asked
Questions
Everything you need to know about this tool, how it works, and what to expect from the results.
Support team · avg 2h reply
Still have questions?
Our support team is available Mon–Fri, 9am–6pm EST. We typically respond within 2 hours.
Contact SupportA reorder point is the inventory level at which you should place a new purchase order to replenish stock before it runs out. It accounts for the time it takes to receive new inventory (lead time) and a buffer for demand variability (safety stock). When your on-hand quantity drops to the reorder point, it triggers a replenishment order.
The reorder point formula is: Reorder Point = (Average Daily Usage x Lead Time in Days) + Safety Stock. Average daily usage is the typical number of units sold or consumed per day. Safety stock is a buffer quantity that protects against unexpected demand spikes or supplier delays.
Safety stock is the extra inventory kept on hand as a buffer against variability in demand or supply. The reorder point is the total inventory level that triggers a new order and includes safety stock plus the expected usage during lead time. Safety stock is a component of the reorder point calculation, not a separate trigger.
Divide your total units sold over a period by the number of days in that period. For example, if you sold 600 units over 30 days, your average daily usage is 20 units. Use at least 30 to 90 days of data to smooth out short-term fluctuations and get a reliable average.
Lead time is the number of days between placing a purchase order with a supplier and receiving the goods in your warehouse ready for sale. It includes manufacturing time, shipping time, customs clearance for international orders, and receiving and inspection time. Longer or more variable lead times require higher reorder points.
Recalculate reorder points at least quarterly or whenever there is a significant change in demand patterns, supplier lead times, or business conditions. Seasonal products may need monthly adjustments. If you use inventory management software, configure it to recalculate reorder points automatically based on rolling sales data.
A reorder point set too high causes excess inventory, tying up cash and increasing storage and carrying costs. A reorder point set too low leads to stockouts, lost sales, and potentially lost customers. The goal is to balance carrying costs against the risk and cost of running out of stock.
The reorder point tells you when to order while EOQ (Economic Order Quantity) tells you how much to order. Together they form a complete inventory replenishment policy. When inventory drops to the reorder point, you place an order for the EOQ quantity to minimize the combined cost of ordering and holding inventory.
Related Tools
Safety Stock Calculator
Calculate optimal safety stock levels and reorder points to prevent stockouts while minimizing excess inventory holding costs.
Use Tool →EOQ Calculator
Calculate Economic Order Quantity using annual demand, order cost, and holding cost. Download a PDF report with a worked example.
Use Tool →Demand Forecaster
Project future order volumes for the next 12 months based on historical sales data, growth trends, and seasonal patterns.
Use Tool →