In this article

01 The percentages start with different audiences

02 One Google visit keeps someone in the shared audience

Google reached 93.7% of ChatGPT’s website visitors in September 2026, according to Similarweb’s audience figures . Looking at the overlap from the other direction, 14.1% of Google’s visitors also visited ChatGPT.

The comparison covers Google.com and ChatGPT.com worldwide. Similarweb clarified in a reply that it counts unique monthly visitors who visited both sites, rather than raw sessions. It therefore concerns shared web audiences, not combined use across websites and apps.

The figures were highlighted by SEO consultant Gagan Ghotra . The published data contains no purchase tracking or information about which service people visited first.

Similarweb's original worldwide web-audience overlap chart, published with its September 2026 figures. Image: Similarweb

The percentages start with different audiences

Similarweb uses each website’s own visitor base as the starting point.…