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A shopper stops in front of the shelf, looks at the empty space and walks away. For them the story ends there. For the chain it started much earlier, and next week's report may not even register that it happened. That scene has a name: an out-of-stock.
This page is a summary of the whole topic. Each section answers one question in a few paragraphs and points to where it is covered in full.
What an out-of-stock is
An out-of-stock is the absence of the product at the point where the customer reaches for it.
The definition looks obvious and it is not. What counts is the shelf, not the stock. An item that arrived at the store, sits in the stockroom and never made it to the shelf is an out-of-stock for whoever came to buy it, even with a positive balance in the system and a green availability report.
Three definitions are in use across the industry and they disagree with each other about that same case. How to measure retail out-of-stocks puts the three side by side.
Out-of-stocks and waste are opposite problems
The two terms show up in the same meeting and mean opposite things.
An out-of-stock is the sale that did not happen because the product was missing. It is margin you never earned.
Waste is the product you already bought and lost before selling it: expired, unfit for consumption, damaged. It is money you have already spent.
In the ABRAS survey, theft does not count as waste: it is classified separately, as operational deviation.
One measures what never came in. The other measures what went out and never came back.
Brazil has an industry-wide measurement for waste. ABRAS publishes the Operational Efficiency Survey, and the figures below come from the Smart Market ABRAS 2026 presentation. The operational inefficiency index for food retail came in at 1.82%, against 1.89% in the previous reading. The breakdown by store format in that presentation is the 2025 one, and the spread between formats is wide:
| format | operational inefficiency |
|---|---|
| wholesale and cash-and-carry | 1,54% |
| hypermarket | 1,66% |
| convenience store | 1,70% |
| conventional supermarket | 2,15% |
| in-building and container stores | 2,75% |
| neighborhood store | 3,27% |
Operational inefficiency by store format, from the Smart Market ABRAS 2026 presentation, on the 2025 slide.
The survey groups losses into three blocks. Operational waste is the largest of them, at 62%, followed by operational deviation at 21% and administrative at 17%.
And here is the number that matters to anyone dealing with out-of-stocks: within operational waste, the single largest cause is expiry, at 41%, followed by product unfit for consumption at 25% and damaged product at 21%.
Why that matters: the two sides pull the order in opposite directions. Buying more lowers the chance of running out and raises exposure to expiry, which is the largest cause of waste. In perishables a buyer cannot simply raise the order and sleep easy.
The two types of out-of-stock
One question separates them: where is the product at the moment the customer cannot find it.
If it is in the store, in the stockroom or at the distribution center, it is a shelf out-of-stock. The product is already yours, the money is already spent, and the problem is replenishment.
If it is nowhere in the chain, it is a systemic out-of-stock. The order or the forecast failed.
There is a third case that operations know well and that is neither one nor the other: the product is sitting in one store and missing in another in the same chain. That is a shortage between units, and the problem there is distribution, not buying and not replenishment.
The distinction is not vocabulary. The three cases have different causes, different owners and different fixes, and there are indicators on the market that see the systemic out-of-stock and miss the shelf one. How to measure retail out-of-stocks goes into which ones.
How to calculate the out-of-stock rate: the formula in one line
The out-of-stock rate is the share of items that should be on sale and are not:
out-of-stock rate (%) = missing items ÷ items sold by the store × 100
The arithmetic is simple. What changes everything is what you count as missing and when: the shelf or the whole store, in the morning or at the end of the day. Change that and the number moves without anything moving inside the store.
To turn it into money there is a second calculation, with three factors, because the rate counts items and not currency:
lost sales = revenue × sales-weighted out-of-stock rate × the share that is never recovered
What out-of-stocks really cost explains where each term comes from and the three most common errors. For the number from your own operation without doing the math by hand, use the out-of-stock calculator.
Out-of-stock examples in a supermarket: four scenes
Bread at six in the evening. The bakery planned its production for the morning peak. By the end of the day the shelf is empty and there is no stockroom to fall back on, because the product is made in the store. It is an out-of-stock with no inventory involved at all, and it only shows up in the indicator if the count happens at the end of the day.
Produce on Thursday. The buyer knows the weekend pulls sales up. Order for the average and it runs out on Saturday. Order for the peak and it is left over on Monday and turns into waste. It is the tension between the two calculations inside a single decision, in the department where it hurts most.
The promotion that worked. The flyer went out, sales tripled, and the order had been placed on the average of the previous weeks. The product runs out on day two of a five-day campaign. The cause is not in the store, it is in the order.
The new code. The supplier changed the packaging and the item started coming in under a different code. The new one is not in the store's assortment yet, the old one still shows a balance in the system, and the shelf stays empty without any report flagging it. The cause is not in the store and not in the order, it is in the assortment decision.
All four are out-of-stocks. Only one of them is solved by buying more without creating another problem.
How to prevent them
There is no shortcut, but there is an order.
Separate the two types before acting, because shelf replenishment and ordering errors belong to different teams and no single action fixes both. And look at perishables together with waste, never on their own, because in that group the decision to buy more has a known price and that price is expiry.
Once that separation is made, forecasting comes in. You can anticipate the shortage from the data the operation already produces, before the shelf empties, and that is what replenishment with AIcovers. INTEGRA is the Integrity-UX platform that does this work on the data the chain already has.
And if the question is what the largest chains in the world are doing about it, out-of-stocks in grocery retail gathers what came out of NRF 2026.
Frequently asked questions
What is the difference between an out-of-stock and waste?
An out-of-stock is the sale that did not happen because the product was missing from the shelf. Waste is the product the store bought and lost before selling it, through expiry, product unfit for consumption, or damage. Theft, in the ABRAS classification, is operational deviation, not waste. One is margin that never came in, the other is money already spent.
How do you calculate the out-of-stock rate?
Divide the missing items by the items the store carries in the period. The result is a count of products, not of money. To turn it into currency, the rate has to be weighted by each item's sales, and the out-of-stock calculator does the math.
Does buying more stock fix out-of-stocks?
Only the systemic kind, where the product does not exist in the chain. In a shelf out-of-stock the product is already yours and sitting in the building, so buying more changes nothing. And in perishables, buying more raises waste from expiry, which is the largest cause of operational waste according to ABRAS.
