Reorder Point Calculator

Reorder point = (average daily demand x lead time in days) + safety stock. The first part is your lead time demand, the units you expect to sell while you wait for a new order to arrive. Safety stock is an extra buffer against demand spikes or supplier delays. When stock on hand falls to the reorder point, you place your next order.

If your demand and lead times are steady, a simple rule of thumb (for example a few days of average demand) is fine. If they vary, use the service-level method: safety stock = z x demand standard deviation x square root of lead time, where z reflects how often you want to avoid a stockout. This tool can compute that buffer for you from a 90%, 95%, 97.5% or 99% service level.

Service level is the probability you will not run out of stock during the lead time. A 95% service level (z = 1.645) means you expect to be in stock about 95% of cycles. Higher service levels need more safety stock, so they tie up more cash; common choices are 90%, 95%, 97.5% and 99%. Pick higher levels for bestsellers and items with long or unreliable lead times.

Use consistent units throughout. Daily demand and safety stock are in product units, and lead time is in days. The reorder point comes back in the same product units, so when your on-hand quantity reaches that number it is time to reorder.

Yes. A longer lead time, higher demand or a larger safety buffer all raise the reorder point, which means you trigger orders sooner and hold more inventory on average. The goal is a level that comfortably covers demand during the lead time without overstocking and tying up cash in slow-moving goods.

No. The calculation runs entirely in your browser. Nothing you enter is uploaded, logged or stored.