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8.7Intermediate6 min

Share of Voice: Measuring Search Market Share

Lucas Blochberger··Updated 20 April 2026
Definition

Share of Voice (SoV) in SEO measures the percentage of total organic visibility a brand captures for a defined keyword set compared to competitors. It serves as a proxy for market share in organic search.

Key Takeaways

  • SOV measures the relative share of organic visibility
  • Calculation: Your organic clicks / Total organic clicks for keyword set
  • Sistrix Visibility Index is the DACH standard metric
  • SOV correlates with Share of Market
  • Share of Model extends SOV to AI visibility

Share of Voice provides strategic overview: How does your website compare to the competition?

Calculate SOV

Define a relevant keyword set. Measure the estimated organic CTR for each keyword based on your position. Compare with competitors. Your share of total organic visibility = SOV.

Sistrix Visibility Index

In the DACH region, the Sistrix Visibility Index is the standard SOV metric. It aggregates rankings and search volumes into a single comparable value. Historical data since 2008 enables long-term comparisons.

Share of Model: SOV for AI

Share of Model extends the SOV concept to AI search systems. It measures how frequently a brand is mentioned in AI-generated answers, compared to competitors. Tools: Profound, Ahrefs Brand Radar, Semrush AI Visibility.

Share of Voice is the closest metric we have to market share in organic search. It tells you how visible you are relative to your competitors across all relevant queries.

Kevin Indig, Growth Advisor, Former VP SEO Shopify

FAQ

How do I calculate Share of Voice?
Define a keyword set (50-200 keywords). Measure organic clicks for each keyword across all competitors (via Ahrefs/Semrush). Your share of total clicks = SOV. Easier: Use Sistrix Visibility Index as a proxy.