What is share of shelf?
The idea started in physical retail, where it meant how much shelf space and how many facings a brand's products had in a store aisle.
Online, the shelf is a results page. Digital share of shelf looks at how often and how high a brand's products appear when shoppers search or browse a category, in both organic and sponsored positions.
How is share of shelf measured?
| Channel | What is counted | Example measure |
|---|---|---|
| Physical store | Shelf space or product facings | A brand's facings divided by all facings in the category |
| Retailer search | Appearances in results for category searches | Share of the top results that belong to the brand |
| Category pages | Placement in browse listings | Share of first-page listings |
| Sponsored placements | Paid positions won | Share of sponsored slots |
Counting positions is the easy part. The harder part is deciding which searches and aisles define the category, because the share changes with that choice.
What is an example of share of shelf?
Visible but not chosen
A snack brand appears in a large share of first-page results for its category on a major retailer, yet its share of category purchases is slipping.
Comparing product views with purchases shows shoppers are seeing the brand but choosing a competitor, so the problem is conversion, such as price, reviews, or content, not visibility.
Share of shelf vs. share of category vs. market share
| Share of shelf | Share of category | Market share | |
|---|---|---|---|
| What it measures | Visibility at a retailer | A brand's share of category purchases | Share of total sales in a market |
| Where it's read | Store aisle or results page | Per retailer, often weekly | Across the whole market |
| What it signals | Opportunity to be bought | Who is winning shoppers | Overall competitive position |
Why does share of shelf matter?
Shoppers can only buy what they see. On a crowded digital shelf, a brand that slips off the first page loses consideration before price or quality comes into play. It sits alongside share of search and share of voice: together they show whether a brand is found, talked about, and chosen.
- An early indicator. Visibility often shifts before sales do.
- Diagnoses the funnel. A brand that's seen but not bought has a different problem from one that isn't seen at all.
- Guides retail media. Sponsored spend can fill visibility gaps where organic presence is weak.
How does Alli do this?
Alli by PMG's Commerce Insights measures share of category: a brand's portion of the category total, and how it moves week to week, on each of nine major retailers. It tracks purchases, product views, and organic search clicks with the same base metrics everywhere, so visibility and conversion can be compared on equal terms.
Comparing product views, organic search clicks, and purchases shows where shoppers drop off, so teams know whether the problem is visibility, consideration, or conversion before they spend to fix it.
Explore Alli Commerce InsightsShare of shelf FAQ
What is digital share of shelf?
The share of a category's online visibility a brand holds at a retailer, based on how often and how high its products appear in search results, category pages, and sponsored placements.
How do you calculate share of shelf?
Divide the brand's visible positions, such as facings in store or first-page results online, by the total positions in the category, for a defined set of searches or aisles.
What is the difference between share of shelf and market share?
Share of shelf measures visibility. Market share measures sales. Visibility gives a brand the chance to win sales, so the two usually move together but not always.
How can a brand improve share of shelf?
Strengthen product content and reviews to rank better organically, use sponsored placements where organic presence is weak, and focus on the retailers where category demand is growing.
Last updated ‹ Back to the glossary