Reorder point & safety stock calculator

Know exactly when to reorder so you do not run out. Free, private, runs in your browser.

How it works

  • Reorder point = Average daily demand × Lead time + Safety stock
  • Max − average method: Safety stock = Max daily demand × Max lead time − Average daily demand × Average lead time
  • Statistical method: Safety stock = Z × σ(daily demand) × √Lead time

Example: 20/day, 7-day lead time, max 30/day and 10 days → safety stock 300 − 140 = 160, reorder point 300 units.

Learn more

Reorder point and safety stock: formulas with examplesHow to calculate reorder point and safety stock: lead-time demand, the max-minus-average method and the service-level (statistical) method, with worked examples for a small shop.

FAQ

Which method should I use?

Max − average is simple and needs no statistics. The statistical method lets you choose a service level when you have demand history.

What is a service level?

The probability of not running out during a replenishment cycle. Higher levels need more safety stock.

What if lead time also varies?

The statistical formula here assumes a stable lead time. If lead time varies a lot, the max − average method is a reasonable safeguard.

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