How often are we losing sales to out of stock?
№ 059 · Stockout rate
Definition
MetricShare of SKUs or SKU-days unavailable to purchase
Unit% of listed SKUs out of stock
Percent of SKU-days where inventory hit zero. Spikes during peak. Build by counting (SKU times day) pairs with zero inventory and dividing by total SKU-day combinations. Lost-sales signal. Example: 4.2% baseline, 12% during Black Friday week (revenue gone).
- SKU
- Stock keeping unit. One distinct sellable variant. Counted at the variant level, not the product level.
Benchmarks
| Bottom 30% | Median | Top 30% |
|---|---|---|
| 10%+, and roughly double the base rate on promoted items | 8% to 8.6% | under 3% to 4% (on-shelf availability 96% to 97%+) |
Retail and ecommerce blended, global. The 8.3% anchor is the GMA global study of 71,000+ consumers across 29 countries and has been re-confirmed at 8.6% in Europe by ECR Retail Loss. Definition used here: SKU-level unavailability as a share of listed SKUs. · The two most-cited anchors are old. The 8.3% global figure dates from the GMA study of 2002 and the promoted-items-are-twice-as-bad finding from ECR Europe in 2003, both carried forward in current literature because later reviews keep landing in the same range rather than because they have been re-run at that scale. Treat them as durable order-of-magnitude anchors in a 2026 reference, not as current measurements. Definition mismatch is the larger practical problem: event-based rates, time-based rates (share of selling time lost) and demand-based rates (unfulfilled demand) are different metrics and are routinely compared as if they were one. Online adds a specific distortion, since an item can show as unavailable when available-to-promise hits zero while units exist elsewhere in the network, and can show as available after the last unit is committed if sync lags.
| Category | Bottom 30% | Median | Top 30% |
|---|---|---|---|
| Grocery and food | 12%+ | 7% to 9.5% | 5% |
| General retail and ecommerce blended | 10%+ | 8% to 8.6% | 3% to 4% |
| Promoted and discounted lines | 20%+ | 10% to 16% | 6% |
When it looks bad
The stockout line spikes precisely on promotion weeks and on the top-velocity SKUs rather than spreading evenly across the tail, so the business is going out of stock exactly on the demand it paid to create.
Blended stockout runs 6% but the promoted subset hits 17% in week two of each campaign, and the ten highest-velocity SKUs account for 40% of lost availability days. At a 4%-of-sales cost of stockouts, that concentration is worth more than the promotion's incremental margin.
What to do about it
- Measure availability on your top-velocity decile separately from the blended rate, daily rather than periodically. A blended number that includes a long tail of low-velocity SKUs will not move when the SKUs that carry revenue go dark.
- Fix inventory-record accuracy before buying forecasting software. Controlled tests show correcting inventory records alone has produced 4% to 8% sales uplift, because system stock and actual available stock diverge long before the forecast is the constraint.
- Uplift safety stock on promoted lines specifically, since promoted items go out of stock at roughly twice the base rate. Promotions concentrate demand into a window narrower than the replenishment cycle, so the base service level is structurally wrong for them.
- Instrument the substitution path rather than only the availability rate. Roughly 31% of shoppers buy the missing item elsewhere and about 9% abandon the purchase entirely, so a back-in-stock capture and a ranked substitute recommendation recover demand the availability fix cannot reach in time.
Sources
- Pygmalios (compiling GMA, ECR Retail Loss, IHL, Corsten and Gruen) Global average out-of-stock rate 8.3% (GMA, 2002) with ECR Retail Loss reporting about 8.6% across Europe; world-class performers run on-shelf availability of 96% to 97%+, meaning out-of-stock at or below 3% to 4% pygmalios.com ↗
- Pygmalios (compiling ECR Europe and Corsten and Gruen) Promoted items go out of stock at roughly twice the rate of non-promoted items; stock-outs cost about 4% of sales, roughly $40M a year for a billion-dollar retailer; when an item is missing about 31% of shoppers buy it elsewhere and about 9% do not buy at all pygmalios.com ↗
- Xorosoft (citing IHL Group and Purdue University) IHL puts global inventory distortion at $1.7 trillion, 6.2% of global retail sales, with 65.6% attributed to out-of-stocks; US food out-of-stock rate 9.5% in 2024, down from 12.3% in 2023 and 19.3% in 2022 xorosoft.com ↗
- Opensend Typical ecommerce out-of-stock rate 2% to 5% under normal conditions with about 8% used as a practical blended benchmark, rising to 10% for promoted or discounted items opensend.com ↗
- Opensend Industry leaders maintain rates below 5%; 60% of online brands face stockout situations weekly; stockouts are implicated in roughly 20% of cart abandonments opensend.com ↗
- Pazo Strong on-shelf availability falls between 95% and 98%, with measurable revenue leakage beginning below 95%, and OSA must be measured daily or weekly rather than periodically gopazo.com ↗
- Pygmalios (citing ECR Retail Loss and IHL/Scandit) Correcting inventory-record accuracy alone has produced 4% to 8% sales uplifts in controlled tests, and only 7% of surveyed retailers use any form of video analytics for shelf monitoring pygmalios.com ↗