Reorder Point Calculator
A reorder point is the inventory level that triggers a new purchase order. It equals your average daily sales times supplier lead time, plus safety stock, so new units arrive before you run out. Enter your numbers below to get your reorder point and statistical safety stock instantly.
Add your current stock on hand to see whether it's time to reorder.
The formula
Worked example
Selling 20 units/day with a 10-day lead time, a 95% service level (Z = 1.65) and a demand std. deviation of 6 units: safety stock = 1.65 × 6 × √10 ≈ 32, and reorder point = (20 × 10) + 32 = 232 units. When stock falls to 232, reorder.
Stop calculating by hand
Logistified computes this across your whole Shopify catalog automatically — from live sales data — and turns it into reorder alerts and purchase orders.
Frequently asked
What is a reorder point?
A reorder point is the inventory level that triggers a new purchase order. It equals average daily sales times supplier lead time, plus safety stock — so fresh units arrive before you run out. It tells you when to reorder, not how much.
How is the safety stock here calculated?
This tool uses the statistical method: safety stock = Z × standard deviation of daily demand × √(lead time), where Z comes from your target service level (95% ≈ 1.65). Higher service levels need more buffer. If you don't know your demand standard deviation, ~30% of average daily sales is a reasonable starting estimate.
What's the difference between reorder point and EOQ?
The reorder point tells you when to place an order; the economic order quantity (EOQ) tells you how much to order each time. Use them together: reorder when stock hits the reorder point, and order the EOQ amount.
Why does lead time use a square root?
Demand variability accumulates over the lead time, but variances add — so the buffer scales with the square root of lead time, not lead time itself. Doubling lead time increases safety stock by about 1.4×, not 2×.