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Reorder Point Calculator: When to Reorder

Find the stock level at which to place the next order: daily demand × lead time + safety stock, with the safety stock entered or worked out from a service level.

Reorder point

630units

Demand during lead time

480units

Safety stock

150units

Order now?

Yes: stock is at or below the reorder point

Reorder point = daily demand × lead time + safety stock

Reorder point formula

The reorder point (ROP) is the stock level that triggers a new purchase order. Order when stock falls to this level and the new delivery arrives just as the safety stock is reached, so you do not run out while you wait.

Reorder point formula

Reorder point = average daily demand × lead time in days + safety stock

Example: you sell 40 units a day, the supplier takes 12 days, and you keep 150 units of safety stock. ROP = 40 × 12 + 150 = 630 units. With 520 units on the shelf, it is time to order.

Safety stock from a service level

If you do not have a safety stock figure, the calculator works it out: Z × standard deviation of daily demand × √lead time. Z depends on how often you accept a stockout: 1.65 for 95% of cycles without a stockout, 2.33 for 99%.

Keep the inputs current

  • Use recent demand, and season it: a summer item needs a summer daily rate.
  • Use the real lead time from order to goods on the shelf, not the supplier's quote. The lead time calculator helps.
  • Set how much to order with the EOQ calculator and the buffer with the safety stock calculator.

Copy the result, or save it as a PDF to attach to an email or a report. Nothing you type leaves your browser.

Features

  • Lead time demand
  • Safety stock entered or from service level
  • Reorder point in units
  • Order now check against stock on hand
  • Formula shown
  • Copy or PDF

Frequently asked questions

What is the reorder point formula?

Daily demand × lead time + safety stock. 50 a day with a 10 day lead time and 100 safety stock gives 600.

Is the reorder point the same as the order quantity?

No. The reorder point says when to order; the order quantity (for example the EOQ) says how much.

Does the reorder point include stock already on order?

Compare the reorder point with stock on hand plus stock on order that has not arrived, minus orders you have promised to customers.

Is the calculator free?

Yes. No sign up. It runs in your browser, and you can copy the result or save it as a PDF.

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