Inventory planning

Inventory Reorder Point Calculator

Calculate an inventory reorder point from daily usage, supplier lead time and safety stock. See lead-time demand and the stock threshold for a purchase review.

Enter the figures you want to check

From 0 to 1,000,000 units per day, with at most two decimal places.

A whole number from 0 to 3,650 days.

A whole number from 0 to 1,000,000,000 units.

Calculations run only in your browser. Values are neither saved nor sent to us.

How are the results calculated?

Usage during lead time = average daily usage × lead time in days.

Reorder point = usage during lead time + safety stock, rounded up to a whole unit.

Assumptions and limits

  • Use one consistent stock unit and the same day basis for average usage and lead time. You supply the safety stock amount; the tool does not statistically estimate demand variability or supplier delays.
  • The reorder point is a review threshold, not a suggested order quantity. Consider incoming orders, reserved stock and seasonality before buying. The tool does not create purchase orders or change inventory.

Understand the idea behind the calculation

Using the tool and understanding your results

Find the stock level that prompts a review of your next purchase. Enter average daily usage, supplier lead time and your chosen safety stock to calculate expected lead-time usage and a reorder threshold in units.

How do I calculate an inventory reorder point?

Multiply average daily usage by lead time in days, then add safety stock. At 20 units a day, a 7-day lead time and 30 safety units, lead-time usage is 140 units and the reorder point is 170 units.

Is the reorder point the quantity I should order?

The reorder point is a stock threshold for reviewing a purchase, not the order quantity. Choosing an order size also requires reviewing incoming orders, reserved stock, expected demand and supply conditions.

How do I use safety stock in the calculator?

Enter the safety quantity you use for the item in the same unit as daily usage. The calculator adds it to lead-time demand and rounds the final threshold up to a whole unit; it does not estimate safety stock from demand variability.

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