Calculators / Reorder point

Reorder point calculator

Enter how fast the item sells and how long your supplier takes. You get the stock level to reorder at, and how long you have until then.

Your numbers

From placing the order to stock ready to sell.
Extra days of sales to hold as a buffer.

Stock plan

Sold during lead time
Safety stock
Reorder point
Days until you reorder
Days until you run out

The formula

Reorder point = daily sales × lead time + safety stock
Safety stock = daily sales × safety days
Days until reorder = (stock now − reorder point) ÷ daily sales

Worked example

A water bottle sells about 14 a day. The supplier takes21 days from order to delivery, and you want a week of sales as a buffer. There are 600 in stock today.

Sold during lead time14 × 21 = 294
Safety stock14 × 7 = 98
Reorder point294 + 98 = 392 units
Days until reorder(600 − 392) ÷ 14 = 14.9 days

So the order goes in about two weeks from now. Put a reminder in for day 13 rather than day 15; being a day early costs almost nothing.

When the simple formula is not enough

Seasonal products

The formula uses average sales. If the next few weeks are your busy season, use the daily sales you expect then, not last month's average, or the reorder will arrive after the rush.

Minimum order quantities

The reorder point tells you when to order, not how much. If the supplier has a minimum order, check you can sell that many before the item goes stale or storage fees pile up.

Selling through Amazon FBA

Add the days it takes Amazon to receive and check in a shipment to your lead time. Those days are often longer than the trip from the supplier.

Read more

Formula and examples last checked October 9, 2026.

Questions people ask

What is a reorder point?

The stock level at which you place your next order with the supplier. If you reorder exactly when stock hits that number, the new stock should arrive around the time your safety stock is all that is left.

How do I find my average daily sales?

Take units sold over the last 30 to 90 days and divide by the number of days. Leave out days when the item was out of stock, or the average will come out too low and you will run out again.

What should lead time include?

Everything from the day you place the order to the day the stock can be sold: the supplier's production time, shipping, customs, and the time it takes to check in the delivery or for a fulfillment warehouse to receive it. Use a realistic figure from your last few orders, not the supplier's best case.

How much safety stock do I need?

Enough to cover the gap when sales run faster or delivery runs later than usual. A simple starting point is a week or two of average sales. If your supplier is often late or your sales jump around, hold more. The cost of holding extra stock is usually lower than losing the listing's sales history to a stockout.

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