Share of search is a brand measurement metric that captures the percentage of all search queries in a category that include your brand name — calculated as your branded search volume divided by total branded search volume for all brands in the category.
Formula: Share of Search = [Brand search volume] ÷ [Total category brand searches] × 100
Why share of search matters
Research by marketing analyst Les Binet and others has shown that share of search is a strong predictor of market share — often leading market share changes by 6–12 months. Brands gaining share of search tend to gain market share; brands losing it tend to lose market share.
Share of search is easier and cheaper to measure than brand awareness surveys, and it updates continuously with publicly available search data (Google Keyword Planner, SEMrush, Ahrefs).
Share of search in the AI era
As AI engines intercept more queries before they become branded Google searches, share of search data faces two complications:
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Zero-click AI responses: Users who get their answer from an AI engine don’t subsequently Google your brand — even if they were influenced by the mention. Share of search may understate actual AI-driven brand awareness.
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AI query patterns differ from search patterns: Users phrase AI queries conversationally and categorically, while branded search captures navigational intent. AI share of voice is a separate metric that captures a different slice of brand presence.
Using share of search alongside AI visibility metrics
The two metrics complement each other:
- Share of search: Captures navigational intent (buyers who already know you and are looking for you)
- AI share of voice: Captures discovery intent (buyers asking AI engines what brands exist)
A brand with high share of search but declining AI share of voice is living off its existing reputation while losing ground with new buyers. The inverse is equally informative.