Inventory & Operations
Inventory Reorder Point Calculator
The Inventory Reorder Point Calculator tells you the stock level at which you should place a new order to avoid running out before replenishment arrives. It computes your reorder point, safety stock, days of stock remaining, days until you must reorder, your Economic Order Quantity, inventory turnover, and current inventory value. The result is a clear trigger point and a stockout-risk read on your current inventory.
Who it's for: Shopify and DTC operators managing physical inventory who need a reliable reorder trigger that accounts for supplier lead time and demand.
How the Inventory Reorder Point Calculator works
You enter average daily sales, lead time in days, safety stock in days, current stock, an optional order quantity, and unit cost. Safety stock is daily sales times your safety-stock days, and the reorder point is lead-time demand (daily sales times lead time) plus that safety stock.
The tool calculates how many days of stock you have left at your current sales rate and how many days remain until you hit the reorder point. It assigns a stockout risk: critical below safety stock, high below the reorder point (order now), medium when approaching it, and low when healthy.
It estimates Economic Order Quantity using annual demand, a 20 percent holding cost, and an assumed 50 order cost, then compares your order quantity to that EOQ to flag over- or under-ordering. Inventory turnover and days-on-hand round out the picture, with low turnover and thin safety stock surfaced as recommendations.
The formula
Safety stock = average daily sales x safety stock days. Reorder point = (average daily sales x lead time days) + safety stock. Days of stock = current stock / average daily sales. EOQ = square root of ((2 x annual demand x order cost) / holding cost per unit), where holding cost = unit cost x 20%.
Frequently asked questions
How is the reorder point calculated?+
The reorder point is the demand you expect during the supplier lead time plus your safety stock. If you sell 30 units a day and lead time is 23 days, lead-time demand is 690 units, and adding a 7-day safety stock of 210 units gives a reorder point of 900. When stock drops to that level, you place the order so new inventory arrives before you run out.
What is safety stock and how much should I hold?+
Safety stock is a buffer that protects you against demand spikes and supply delays, expressed here as a number of days of sales. Seven to fourteen days is typical. The tool warns if you hold less than seven days, because too little buffer leaves you exposed to stockouts when sales surge or a shipment is late, while too much ties up cash.
What is Economic Order Quantity and why compare my order to it?+
EOQ is the order size that minimizes the combined cost of holding inventory and placing orders. Ordering far above EOQ inflates holding costs by tying up cash and warehouse space, while ordering far below it means too many small orders and higher per-order costs. The tool flags when your order quantity deviates from EOQ by more than 30 percent so you can rebalance.
What does inventory turnover tell me?+
Turnover is how many times per year you sell through your average inventory. The tool treats below 4x as low, suggesting overstocking or slow sell-through that ties up cash, and above 12x as very high, which is efficient but raises stockout risk if you cut it too fine. Healthy turnover keeps cash moving without leaving you short of stock.