March 13, 2026 — A study by Graphite.io reveals that AI assistants dominate 56% of global search volume, with 45 billion monthly sessions worldwide and ChatGPT capturing 89%, marking a significant shift in online search behavior driven by tools like ChatGPT, Gemini, Perplexity, Grok and Claude.
The analysis, titled “AI Is Much Bigger Than You Think” and authored by CEO Ethan Smith, combines Similarweb data on web traffic and mobile apps, where 83% of global AI usage occurs. In the US, AI accounts for 34% of search volume with 5.4 billion sessions. Adjusting for search-like “asking” prompts—which represent 28% globally and 17% in the US—the figures underscore AI’s growing parity with traditional search engines.
Total search plus AI volume has grown 26% year-over-year worldwide since 2023, with Google’s share declining from 89% to 71% in Q4 2025.
Key Statistics from the Study
The public Google Sheet details 45.2 billion AI sessions, confirming AI assistants dominate 56% of global search volume, with 45 billion monthly sessions worldwide and ChatGPT capturing 89%. ChatGPT alone drives 40.4 billion sessions, or 89.42% of AI total.
“We originally sought to evaluate our hypothesis that most claims about the usage of AI were overstated… However, upon closer inspection of the data, we found that… claims… are understated.”
Industry Coverage and Implications
Search Engine Land reported on March 9, highlighting the 300% US AI growth by December 2025 and the need for both SEO and AEO strategies, as AI expands discovery rather than cannibalizing it.
Ignite Visibility’s March 13 roundup emphasized: “A new study from Graphite.io revealed that AI assistants… now account for up to 56% of global search volume… you cannot avoid AI search when planning your SEO strategy.”
SEO Spyglass echoed AI assistants dominate 56% of global search volume, with 45 billion monthly sessions worldwide and ChatGPT capturing 89%, noting adjusted search-related traffic at 20% for ChatGPT.
Reactions and Caveats
Marketing expert Aaron Haynes posted on X: “AI usage isn’t 5% the size of search. It’s 56% worldwide… The pie is getting bigger.” [X post]
Rand Fishkin questioned the web-vs-app weighting in a LinkedIn post. Coverage from Performance Marketing World and others affirms rapid AI adoption outpacing estimates, urging a pivot to AI-optimized content.
The study, focused on AEO, repeats AI assistants dominate 56% of global search volume, with 45 billion monthly sessions worldwide and ChatGPT capturing 89% to highlight the scale previously underestimated by web-only metrics.