Google's AI-generated summaries now appear in 43 percent of US search results, up from 15 percent a year earlier, according to Similarweb's 2026 Generative AI Landscape report.
The figure tracks the share of US searches displaying AI Overviews, the generated summaries that appear at the top of conventional Google results. Google also operates AI Mode, a separate conversational interface for longer queries and follow-up prompts, which uses a technique called query fan-out to split questions into subtopics and run multiple searches in parallel.
Similarweb estimated that visits to Google's AI Mode web experience grew from 126 million in June 2025 to 279 million in May 2026. Google separately reported in May that AI Mode had surpassed one billion monthly users, though that figure covers users rather than web visits and is not directly comparable.
The introduction of AI Mode correlated with a 5.4 percent increase in average Google search length, as users shifted toward longer natural-language queries resembling prompts used with AI assistants rather than traditional keyword combinations.
The broader generative AI market also grew. Similarweb estimated that generative AI websites received an average of 9.5 billion monthly visits between June 2025 and May 2026, up 70 percent year over year. Monthly unique visitors rose 57 percent to 655 million, and mobile app downloads increased 58 percent to 4.4 billion.
The report found that most ChatGPT users continued to use Google, with audience overlap among ChatGPT, Gemini, and Claude indicating that people use multiple services rather than committing exclusively to one platform.
Similarweb said its estimates draw on first-party analytics, anonymised device information, external data partnerships, and publicly available web data, meaning its figures are modelled estimates rather than direct counts from Google.
Sources
Google AI Overviews become more common in search - AI News
Similarweb 2026 Generative AI Landscape report - Similarweb
