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Reorder point calculator

Find the inventory level at which to reorder, from demand, lead time and safety stock.

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Need Reorder point (units)? The Reorder point calculator derives it from Average daily demand (units), Lead time (days), Safety stock (units) in one step. For instance, with Average daily demand (units) = 50, Lead time (days) = 7 and Safety stock (units) = 100 it returns Reorder point (units) = 450.

How to use it

  1. Enter your values: Average daily demand (units), Lead time (days), Safety stock (units).
  2. Read the result instantly: Reorder point (units).
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Frequently asked questions

What does the Reorder point calculator actually compute?

It takes Average daily demand (units), Lead time (days) and Safety stock (units) and derives Reorder point (units) from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

3 values: Average daily demand (units), Lead time (days) and Safety stock (units). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Average daily demand (units) = 50, Lead time (days) = 7 and Safety stock (units) = 100, the calculator returns Reorder point (units) = 450. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Average daily demand (units) = 100, Lead time (days) = 14 and Safety stock (units) = 200 instead, Reorder point (units) goes from 450 to 1,600 — which is why it is worth testing a few scenarios rather than trusting a single figure.

What does it give for smaller values?

Scaled down to Average daily demand (units) = 25, Lead time (days) = 4 and Safety stock (units) = 50, Reorder point (units) comes out at 150. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Running the week: issuing an invoice or a quote, knowing what is in stock and what to reorder, and seeing whether cash covers what is due.

What is the most common mistake?

Reading profit as cash. A profitable month with sixty-day payment terms can still leave the account empty — the two numbers answer different questions.

What is the difference between the Reorder point calculator and the Safety stock calculator?

Both return Reorder point (units). What differs is what they ask for: this one wants Average daily demand (units) and Safety stock (units), the Safety stock calculator wants Service level (%) and Average daily demand. Use whichever matches the numbers you already have.

Is there a tool for the next step?

Takt time calculator is the closest one after this: Compute the takt time — the pace of production needed to meet demand.

What else is worth having open alongside it?

Average collection period calculator and Inventory period calculator — they come up in the same task often enough to be worth a second tab.

Further reading

All guides →
ExplainerThe Reorder Point Is a Quantity That Answers a Question About TimeSelling 100 a day with a ten-day lead time and 300 units of safety stock, you reorder at 1,300 — not because 1,300 is a comfortable level, but because that is what ten days of selling costs.ExplainerA 30 % Sell-Through Is Excellent or Alarming, and the Missing Word Is "When"120 units sold out of 400 received is 30 %. Whether that is a success depends entirely on how long it took, and the rate on its own does not carry the answer.ExplainerFour Points of Service Level Cost 41 % More StockGoing from a 95 % service level to 99 % raises the z-score from 1.645 to 2.326 and the safety stock from 346 units to 488. The last few points of availability are the expensive ones.ExplainerGMROI: the Inventory Number That Outranks MarginGross margin return on inventory investment divides gross margin by the cash tied up in stock. It exists because margin alone ranks products wrongly: a 60% margin turning twice a year loses to a 25% margin turning twelve times.ExplainerThe EOQ Square-Root Formula, and Where It Stops Being TrueEOQ = √(2DS/H) balances ordering cost against holding cost. Its most useful property is how flat the cost curve is around the optimum — and its four failure modes are quantity discounts, lumpy demand, a finite replenishment rate, and the two inputs nobody can measure.ExplainerCost of Goods Sold Is What Left the Shelf, Not What You BoughtOpening stock 40,000, purchases 120,000, closing stock 35,000 — the cost of goods sold is 125,000, and it is larger than the purchases because the shelf gave up 5,000 of what was already there.
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