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The five things a stockout costs you

1. The order you did not get

Easy to see and easy to add up. The units you would have sold, times your margin on each one. Also the smallest piece of the bill.

2. The customer who never comes back

Retail studies usually find that around four in ten shoppers go straight to a competitor when they hit a sold out product. Some of them never come back. You lose everything they would ever have spent, not one order, which makes this far bigger than the lost sale.

3. Ads pointing at a page nobody can buy from

Campaigns almost never pause themselves when stock hits zero, so you keep paying for clicks to a page that cannot take an order. This is pure waste and the easiest of the five to stop, as long as somebody knows the product went out.

4. Losing your place in search results

Marketplaces and your own site search both push down items nobody can buy. You do not get that place back the day you restock, so a few days out of stock can cost you weeks of lost visibility afterwards.

5. The panic restock

Rush freight, a part order at a worse price per unit, or hours of your team's time chasing a supplier. Every one of those is money you would not have spent with a bit more warning.

How much bigger the real number is

Published studies usually put the true cost at between one and a half and three times the lost sale itself. Higher again once you count what those customers would have spent over the years.

Treat that as a rough range rather than a precise figure. It swings a lot with your category, your margin and how easily somebody can buy the same thing elsewhere. Something anyone can get anywhere sits at the top of the range, because those shoppers leave and stay gone. Something special that people will wait for sits at the bottom.

You will see industry figures for retail losses running into the trillions a year. Those headlines make the point and tell you nothing useful about your own store. Work out your own number instead.

How to calculate what a stockout costs you

Per product, per day out of stock:

1. Units sold per day × your margin per unit. That is your direct loss.
2. Add the ad money still being spent on that product each day.
3. Add an estimate for lost customers. Take the people who would have bought, assume some fraction never come back and multiply that by what they would have spent over time rather than on one order.
4. Add a share of the panic restock if you paid for rush shipping.
5. Multiply by days out of stock.

The number that actually costs you the money

Look at which number in that example does the damage. It is not the 250 a day. It is the twelve days.

You cannot control how much people buy. You have limited say over whether your supplier is on time. But you have almost total control over how long something sits at zero before anybody notices. That is the number worth attacking and it is the cheapest of the three to fix.

A store that checks stock once a week goes days without noticing. A store with alerts notices in minutes. On the example above, that gap is the difference between 3,000 and almost nothing.

Cut the days, not the demand

The expensive part of a stockout is how long it runs before anybody spots it. Stockwell emails your team before stock reaches zero, so that gap shrinks from days to minutes.

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