What is a stockout in inventory management?

In inventory management, a stockout is a period when a product has no sellable stock while customers still want it. Orders for it are lost, cancelled or delayed. It is tracked per SKU, and for a multichannel brand, per channel and location too, because a product can be out of stock on one marketplace while units sit in another warehouse.

How do you calculate the stockout rate?

The common measure is SKU-days: stockout rate = SKU-days with zero sellable stock ÷ total SKU-days × 100. Example: 200 SKUs over 30 days is 6,000 SKU-days; if 240 were at zero, the rate is 4%. A second measure is order-level: orders that couldn't be filled from stock ÷ total orders × 100.

What is the cost of a stockout for an online seller?

The direct cost is lost sales: average daily sales × days out × price. A SKU selling 25 a day at ₹799, out for 6 days, puts about ₹1,19,850 at risk. There are indirect costs too: marketplace cancellations if orders were accepted, ad money spent on an unavailable product, and buyers who switch brands.

What is the difference between a stockout and a backorder?

In a stockout, the product can't be bought or the order can't be filled, so the sale is usually lost. In a backorder, the seller still accepts the order and promises to ship it when new stock arrives, with a later delivery date. A backorder keeps the sale but needs the buyer's agreement to wait.

What is the difference between a stockout and overselling?

A stockout means there is nothing left to sell and the listing shows it. Overselling means the listings still showed stock after it had run out, so more orders were accepted than can be filled. Overselling is worse for a marketplace seller, because the extra orders must be cancelled and count against the seller.

What causes stockouts in an ecommerce warehouse?

Common causes are late supplier deliveries, stock received but not yet put away, units on hold or reserved for other orders, damaged stock, and channel stock figures that lag behind the warehouse. Demand spikes from sales, influencer posts or ads cause the rest. Reorder points set for normal weeks can run out early in a festive sale.

How can a brand selling on several marketplaces avoid stockouts during a sale?

Raise the reorder point and safety stock for the sale weeks using last season's daily sales, and order earlier to cover longer supplier lead times. Receive and put away inbound stock before the sale starts. Count fast movers beforehand, keep every channel's stock figure in step with the warehouse, and pause ads on SKUs that are running low.

Is "stock out" the same as "out of stock"?

Yes. "Stockout", "stock out", "stock-out" and "out of stock" all describe the same situation: no sellable stock for a product that customers want. "Stockout" is the usual noun in inventory management, as in "stockout rate", while "out of stock" is the phrase shoppers see on a product page.

What is a stockout?

A stockout is when a product has no sellable stock while customers still want to buy it. The order is lost, cancelled or delayed, or the listing goes inactive. "Stock out", "stock-out" and "out of stock" mean the same thing. For a multichannel brand, a product can be out of stock on one channel while units sit elsewhere.

How stockouts happen in an Indian D2C or omnichannel warehouse

Sellable stock is less than stock on hand. A unit counts as sellable only when it is in the warehouse, put away, not damaged, not on hold and not already promised to another order. A SKU can show 40 units on the shelf and still be out of stock online if all 40 are reserved, waiting for quality check, or not yet put away after the GRN.

Where a multichannel brand runs out

On one channel only: the website shows stock, but a marketplace listing shows zero because its stock figure wasn’t updated.
In one location only: the brand’s own warehouse is empty while units sit in a marketplace fulfilment centre, or the other way round.
On paper only: stock is held or reserved, so it can’t be sold even though it is physically there.

Two ways to measure it

Stockout rate (SKU-days) = SKU-days with zero sellable stock ÷ total SKU-days × 100.
Order-level stockout rate = orders that couldn’t be fulfilled from stock ÷ total orders × 100.

Example: the stockout rate. A brand has 200 active SKUs over 30 days, which is 200 × 30 = 6,000 SKU-days. On 240 of those SKU-days a SKU had zero sellable stock, so the stockout rate is 240 ÷ 6,000 × 100 = 4%. In the same month, 180 of 12,000 orders couldn’t be filled from stock: an order-level stockout rate of 1.5%. All numbers are illustrative.

Example: sales at risk. One SKU sells 25 units a day at ₹799 and is out of stock for 6 days. That is 25 × 6 = 150 units and 150 × ₹799 = ₹1,19,850 of sales at risk, if those buyers don’t wait or come back.

Stockout vs related terms

Term	What it means	Order taken?
Stockout	No sellable stock while demand continues	Usually no; the listing goes inactive or the buyer leaves
Backorder	The order is accepted and filled later, when stock arrives	Yes, with a later delivery date
Overselling	More units sold across channels than you hold	Yes, but some orders can’t be filled and are cancelled
Shortage	Less stock than planned or ordered, such as a short supplier delivery	Depends
Sold out	All units of a limited batch are gone, often with no restock planned	No

Which is worse: a stockout or overstock? Both cost money, in different ways. A stockout loses sales now, can bring marketplace cancellations if orders were already accepted, and sends buyers to other brands. Overstock ties up cash and warehouse space and can turn into dead stock that is sold at a discount or written off. Which costs more depends on the product’s margin, shelf life and season: compare the margin lost per day out of stock with the cost of holding each extra unit.

Causes in a multichannel warehouse

Late inbound: the supplier’s lead time is longer than planned.
Stock received but not yet put away, so it isn’t sellable.
Stock on hold, damaged or reserved for other orders.
Channel stock figures out of step with the warehouse.
A sale spike: a festive sale, an influencer post or an ad that worked.

Preventing stockouts, in general terms

Set a reorder point and safety stock per SKU, and review them before sale seasons.
Shorten the time from truck to shelf: faster GRN and putaway.
Run cycle counts so the system figure matches the shelf.
Keep every channel’s stock figure in step with the warehouse.

Common mistakes

Counting a stockout only when the warehouse hits zero, while a channel has been showing zero for days.
No stockout record, so lost demand is invisible and next season’s forecast starts too low.
Ads left running to an out-of-stock product page.
Treating reserved or held stock as available, which turns a stockout into overselling.

Fill rate = units shipped from stock ÷ units ordered × 100. Example: 11,640 of 12,000 = 97%.
Days of cover = sellable units ÷ average daily sales. Example: 300 units ÷ 25 a day = 12 days.
Lost sales estimate = average daily sales × days out of stock × price. Example: the ₹1,19,850 above.

Stockouts in the Indian context

Sale seasons. Marketplace sale events such as Flipkart’s Big Billion Days and Amazon’s Great Indian Festival, and the Diwali and wedding seasons, lift daily sales sharply. Reorder points and safety stock set for normal weeks can run out early.
Cancellations count against sellers. If a seller accepts an order and then cancels it for lack of stock, that is a cancellation by the seller. Amazon.in’s seller blog (28 September 2020) lists cancellation rate among the measures of account performance and says total order cancellations should be less than 2.5%. Check Seller Central for the current thresholds.
Benchmarks. A “normal” stockout rate varies by category and season, and this page doesn’t quote one. Track your own rate over time.

How Fretron CommerceOS fits

Fretron CommerceOS is order, warehouse and shipping software for Indian D2C, retail and omnichannel consumer brands. It is a separate product from Fretron’s freight TMS.

Questions and answers

What is a stockout in inventory management?: In inventory management, a stockout is a period when a product has no sellable stock while customers still want it. Orders for it are lost, cancelled or delayed. It is tracked per SKU, and for a multichannel brand, per channel and location too, because a product can be out of stock on one marketplace while units sit in another warehouse.
How do you calculate the stockout rate?: The common measure is SKU-days: stockout rate = SKU-days with zero sellable stock ÷ total SKU-days × 100. Example: 200 SKUs over 30 days is 6,000 SKU-days; if 240 were at zero, the rate is 4%. A second measure is order-level: orders that couldn't be filled from stock ÷ total orders × 100.
What is the cost of a stockout for an online seller?: The direct cost is lost sales: average daily sales × days out × price. A SKU selling 25 a day at ₹799, out for 6 days, puts about ₹1,19,850 at risk. There are indirect costs too: marketplace cancellations if orders were accepted, ad money spent on an unavailable product, and buyers who switch brands.
What is the difference between a stockout and a backorder?: In a stockout, the product can't be bought or the order can't be filled, so the sale is usually lost. In a backorder, the seller still accepts the order and promises to ship it when new stock arrives, with a later delivery date. A backorder keeps the sale but needs the buyer's agreement to wait.
What is the difference between a stockout and overselling?: A stockout means there is nothing left to sell and the listing shows it. Overselling means the listings still showed stock after it had run out, so more orders were accepted than can be filled. Overselling is worse for a marketplace seller, because the extra orders must be cancelled and count against the seller.
What causes stockouts in an ecommerce warehouse?: Common causes are late supplier deliveries, stock received but not yet put away, units on hold or reserved for other orders, damaged stock, and channel stock figures that lag behind the warehouse. Demand spikes from sales, influencer posts or ads cause the rest. Reorder points set for normal weeks can run out early in a festive sale.
How can a brand selling on several marketplaces avoid stockouts during a sale?: Raise the reorder point and safety stock for the sale weeks using last season's daily sales, and order earlier to cover longer supplier lead times. Receive and put away inbound stock before the sale starts. Count fast movers beforehand, keep every channel's stock figure in step with the warehouse, and pause ads on SKUs that are running low.
Is "stock out" the same as "out of stock"?: Yes. "Stockout", "stock out", "stock-out" and "out of stock" all describe the same situation: no sellable stock for a product that customers want. "Stockout" is the usual noun in inventory management, as in "stockout rate", while "out of stock" is the phrase shoppers see on a product page.

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Last reviewed: 7 November 2026 by Fretron.

Sources

Things to avoid to ensure your account is not blocked. Amazon.in Seller Blog, 28 September 2020. https://sell.amazon.in/seller-blog/things-to-avoid-to-ensure-your-account-is-not-blocked (accessed 5 Nov 2026).