Free inventory calculator
A reorder point calculator tells you when inventory should be reordered before stock runs out. Use the free calculator below to find reorder point, safety stock, lead time demand, and inventory turnover.
Use reorder point = lead time demand + safety stock. Lead time demand is average daily usage x average lead time.
Enter usage, lead time, current stock, and inventory value. Your numbers never leave your browser.
If stock position is at or below the reorder point, reorder now. Stock position equals inventory on hand plus units already on order.
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This free inventory calculator gives you the core math. The Supply Chain & Operations bundle includes templates for inventory management, MPS, BOMs, warehouse management, manufacturing KPIs, supplier management, and capacity analysis.
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Reorder point = (average daily usage x lead time) + safety stock. Example: sell 20 units a day, supplier lead time is 7 days, and you keep 50 units of safety stock. Reorder point = (20 x 7) + 50 = 190 units.
The basic formula is (max daily usage x max lead time) - (average daily usage x average lead time). A statistical method uses service level and demand variability: safety stock = Z x demand standard deviation x square root of lead time.
Lead time demand is the stock you expect to use while waiting for an order: average daily usage x lead time. It is the core of the reorder point before safety stock.
The reorder point is when to order; reorder quantity is how much to order. EOQ, or economic order quantity, balances ordering costs against holding costs to find an efficient order size.
Inventory turnover = cost of goods sold / average inventory. It shows how many times you sell through stock in a period; higher turnover ties up less cash, but very high turnover can mean stockout risk.
Average daily usage comes from total units sold over a period divided by days. Lead time is the average days between placing recent purchase orders and receiving stock. Getting these two right keeps reorder points close to reality.
Reorder points are not set-and-forget. Recalculate when demand shifts, supplier lead time changes, costs move, seasonality changes, or promotions create a new sales pattern.
A spreadsheet is ideal for calculating and tracking reorder points across a manageable SKU count, and it is free to start. As the catalog grows, inventory software can automate reorder alerts.
The inventory level at which you should place a new order so you do not run out before the new stock arrives.
A common method is (max daily usage x max lead time) minus (average daily usage x average lead time), which buffers against demand and supply variability.
The amount of stock you expect to use during the supplier's lead time: average daily usage times lead time in days.
The reorder point is when to order; the reorder quantity, or EOQ, is how much to order.
It varies by industry; higher turnover frees up cash, but very high turnover can signal stockout risk. Compare against your sector's norms.
Recalculate when demand, supplier lead times, or costs change, and review seasonally so your reorder points track real conditions.
The calculator above is free. If you want a spreadsheet you can customize and keep, these premium Excel and Google Sheets templates go further.
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