ChatGPT sends 0.62% of the traffic Google organic does, 100-site study finds
ChatGPT traffic is a rounding error next to Google organic, according to an analysis of 12 months of GA4 data across 100 websites and more than 145 million sessions. ChatGPT sessions amounted to 0.62% of the volume driven by Google organic, rising to 0.73% once every other large language model was included.
The conversion gap is narrower but still lopsided. Across the 55 sites tracking conversions, ChatGPT visitors converted at more than 4.5 times the rate of Google organic visitors, yet Google still drove 96.5% of total conversions across all channels analysed, roughly 27 times more than all LLMs combined.
The study also found that ChatGPT's referral growth stalled in August 2025 around the release of GPT-5 and has declined since, undercutting earlier predictions that LLM traffic would eventually overtake Google. Of the 100 sites sampled, 45 were not tracking any key events at all.
The argument for brands is that AI search is mostly happening inside Google, through AI Overviews, AI Mode and a ranking system driven by deep learning, rather than in chatbot referrals. The piece points to Google's agentic plans, including Universal Cart, the UCP discovery layer and WebMCP, as the areas worth preparing for, and urges marketers to define and measure conversions before optimising for machines.
Reported by Search Engine Journal ↗
Topics: ChatGPT, Google Search, Measurement