Share of Voice (AI)
AI share of voice is the percentage of tracked AI answers that name your business instead of a competitor's, measured per engine and across repeated prompts, since a single AI answer isn't a reliable sample.
Share of voice is a borrowed term from advertising, where it originally meant your ad spend as a percentage of total category spend. In AI visibility, it means something more direct: out of every tracked answer to a buying question in your trade and city, what percentage name you instead of a competitor.
The tricky part is that AI answers aren't fixed. Ask the same question twice and the list of companies named can change, so measuring share of voice from one prompt run is like measuring market share from one customer's opinion. A real measurement asks the same set of questions repeatedly over time and tracks the pattern.
It also has to be measured per engine, not as one blended number. Profound's research across 100,000 prompts found ChatGPT and Perplexity overlap on only 11% of the domains they cite, with 37.4% of citations ChatGPT-exclusive and 51.6% Perplexity-exclusive. A company with strong share of voice in Perplexity answers can have close to none in ChatGPT answers to the same question. Reporting a single combined share of voice number across engines hides that gap.
Domains referenced per response also differ by engine, which changes how much room there is to be named at all: Google AI Overviews reference about 7.7 domains per response, Perplexity about 7.3, ChatGPT about 5.0, and Copilot about 2.5, according to Profound. Fewer slots means a smaller share of voice is harder to win in engines like Copilot and easier to contest in engines like AI Overviews.
Keep exploring the glossary
- AI VisibilityAI visibility is how consistently a business gets named when AI systems like ChatGPT, Gemini, and Perplexity answer a customer's buying question, measured across repeated prompts and multiple engines rather than a single check.
- Citation (AI answer)In an AI answer, a citation is a source the engine references or links to while generating its response, and the number of sources cited per answer varies widely by engine, from about 2.5 for Copilot up to about 7.7 for Google AI Overviews.
- Prompt VolumePrompt volume is the number of times a buying question gets asked across an AI engine in a measurement, and it needs to be high enough, repeated over time and across engines, to produce a share-of-voice reading you can trust.