AI assistants hit 76B monthly sessions, search comparison dropped

Six AI assistants generated an estimated 76 billion sessions worldwide in September 2026, up 37% from a year earlier, according to Graphite’s updated usage report.

The growth is measurable. The comparison with search engines is not. Graphite’s November update drops its earlier AI-to-search benchmark after new information showed the March edition likely undercounted Google search use from the Android app. Graphite said it “can no longer reliably compare” the size of AI used for search with search engines.

What changed since March?

In March, Graphite said monthly AI sessions equaled 56% of worldwide search usage and 34% of U.S. search usage. Search-related AI use represented 28% globally and 17% in the U.S.

Those search totals came from websites only because apps saw little use. The November report treats Google’s Android app differently. Graphite estimates the app generated 11.8 billion monthly U.S. sessions.

Users rely on the app for image recognition, translation, Google Discover and general search. The agency says it lacks a reliable data source for determining how much of that app use is general search.

The counting rules matter. Similarweb estimates web visits plus mobile app sessions, and Graphite uses those figures in the report. It excludes desktop apps because reliable data for them does not exist. Graphite sells SEO and AEO services; Similarweb sells the data.

The March report’s 56% global AI-to-search figure used the website-only search count. So did its estimate that ChatGPT accounted for 20% of global search-related traffic. The November report does not revisit either number. At publication, the March page still highlights both as major findings, although it now links to the newer report at the top.

What traffic do AI assistants send to websites?

Graphite’s data “suggest that AI accounts for less than 1% of traffic on average” to websites. A separate U.S. chart for the second quarter of 2026 puts organic search at 49 times the volume of AI referrals and paid search at eight times.

AI referral traffic grew 92% year over year worldwide as of July 2026 and 75% in the U.S. The referral sample covers the top 43,000 sites among domains with at least 100,000 monthly U.S. visits for six or more months between July 2023 and July 2026. It tracks referrals to those sites worldwide and in the U.S.

The July referral shares were:

• ChatGPT accounted for 60% of global AI referral traffic, followed by Gemini at 14% and Claude at 10%.
• In the U.S., ChatGPT accounted for 66%, Claude for 11% and Gemini for 10%.

How did usage grow?

Global session activity with the six assistants rose only 2.3% between July and December 2025, which Graphite describes as a plateau. It then rose 19% from January through September 2026 across all the assistants.

• U.S. session activity grew 45% year over year in September.
• ChatGPT grew 24% year over year worldwide and represented 58.9% of the added sessions.
• Claude posted the largest percentage increase globally, at 1,901%, and generated 26% of the additional sessions.
• Perplexity was the only one of the six to decline, falling 27% globally.

Mobile accounted for 89% of global sessions in the third quarter of 2026, whether through a mobile app or mobile web. The U.S. share was 78%.

What does this change for channel plans?

The practical answer: don’t put March’s ratio into a channel plan until someone can show how Google was counted. Graphite’s March Google data came only from website visits; its November work can’t determine what share of total Android app use is general search.

That also limits comparisons with OpenAI. When OpenAI said ChatGPT receives approximately one-fifth as many search-like queries as Google, it provided no actual Google figure. A Nov. 3 analysis covered that claim. The two estimates count different events: OpenAI logs a search whenever a question sends ChatGPT to the web, while Graphite counts website visits and app sessions.

Will AI referrals capture the full effect?

Not reliably. Graphite cites anecdotal evidence that some visits prompted by AI answers get credited as direct visits or branded search, which AI referral reports would miss. Its early numbers show branded search traffic fairly flat year over year, with full results still to come.

That measure is broader than the one in Similarweb’s June data, which an earlier analysis covered. Among people who visited a brand’s site after ChatGPT recommended it, 55.9% of that traffic came through branded search in U.S. desktop data.

For operators, the conclusion is narrower than the headline: AI use is scaling fast, but referrals still represent less than 1% of average site traffic. Track referrals alongside direct and branded search before shifting spend.