Image: Similarweb

ChatGPT still owns more than half of all visits to AI chatbot websites, but its grip has loosened noticeably over the past year. That's according to new estimates from web analytics firm Similarweb, which tracks how worldwide website traffic is split among the biggest generative AI tools.

In its September 2026 update, Similarweb estimates ChatGPT's share of gen AI website traffic at 56.4%. A year earlier, in October 2025, the same tracker put it at 71.8%. Google's Gemini sits in second place at 25.0%, up from 13.6%, while Anthropic's Claude is third at 9.6%, up from 2.3%.

Further down the list, DeepSeek is estimated at 3.4%, Grok at 2.3%, Microsoft's Copilot at 1.5% and Perplexity at 0.9%. All four have lost ground compared with a year ago, when Similarweb had them at 4.1%, 2.8%, 2.0% and 2.5% respectively.

Gen AI website traffic share update - September 2026

🗓️ 12 months ago (October 2025):
ChatGPT: 71.8%
Gemini: 13.6%
DeepSeek: 4.1%
Grok: 2.8%
Perplexity: 2.5%
Claude: 2.3%
Copilot: 2.0% pic.twitter.com/3KQW7T5k0S

— Similarweb (@Similarweb) October 12, 2026

These are third-party estimates based on Similarweb's own traffic modeling, not numbers confirmed by OpenAI, Google, Anthropic or any of the other companies. They also only cover website visits. People who use these assistants through phone apps, or through tools built into Android, Windows or office software, aren't captured in a website traffic share chart, so this is one slice of the picture rather than a full count of users.

Still, the trend lines are worth a look, and a few things stand out when you line up Similarweb's monthly figures.

First, ChatGPT's slide appears to have stopped, at least for now. Its estimated share bottomed out at 53.7% in April 2026 and has crept back up each month since, to 54.3% in July, 55.6% in August and 56.4% in September. So the big shift happened over roughly the first half of the period, not steadily across the whole year.

Second, Gemini's rise has flattened and even slightly reversed. Similarweb had it at 26.7% in April and 26.6% in July, before it slipped to 25.6% in August and 25.0% in September. Gemini still has nearly double the share it had a year ago, but the last few months suggest ChatGPT has been winning some of that ground back.

Third, Claude is the quiet growth story. Its estimated share has roughly quadrupled in a year, from 2.3% to 9.6%, and it has held between 8% and 9.6% since April. That has pushed it past DeepSeek, Grok and Perplexity, which were all ahead of it in October 2025.

Put together, the market looks more concentrated, not less. By our count from Similarweb's figures, ChatGPT, Gemini and Claude together made up about 91% of estimated gen AI website traffic in September, up from about 87.7% a year earlier. The smaller players are being squeezed even as the top of the table reshuffles.

Perplexity's numbers are the starkest example. Its estimated share fell from 2.5% to 0.9% over the year, which puts it below one percent for the second month in a row.

For regular users, the takeaway is simple: ChatGPT is still the default place most people go, but Gemini and Claude are now real alternatives with meaningful audiences. Whether ChatGPT's recent recovery holds, or Gemini picks up speed again, should show up in Similarweb's next few monthly updates.