Similarweb's June 2026 update on generative AI website traffic share reveals a market that has shifted more sharply in twelve months than most forecasts expected - with ChatGPT surrendering nearly a quarter of its worldwide dominance while Anthropic's Claude posted the biggest month-over-month percentage point gain among the tracked platforms.

ChatGPT's 12-month slide: from 76.4% to 52.7%

Twelve months ago, according to Similarweb data published on LinkedIn on June 11, 2026, ChatGPT held 76.4% of worldwide generative AI website traffic. By May 26, 2026 - the measurement date for the June update - that figure had fallen to 52.7%. The arithmetic is blunt: OpenAI's flagship product lost 23.7 percentage points in a single year, roughly two points per month.

The decline was not linear. Six months ago ChatGPT still held 65.2%, meaning the platform shed 11.2 additional percentage points in the second half of that window - a faster pace of erosion than the first six months. Three months ago it stood at 56.7%, and one month ago at 52.7%, suggesting the rate of decline may be stabilising somewhat, though the overall trend remains downward.

PPC Land has tracked this trajectory closely since mid-2025, documenting how ChatGPT fell below 65% for the first time in January 2026, a milestone that at the time appeared significant. The May 26 data now places the platform's share more than 12 points below that level.

Gemini's ascent: 8.9% to 27.3%

Google's Gemini platform is the clearest beneficiary of ChatGPT's retreat. Twelve months ago, according to Similarweb, Gemini accounted for 8.9% of generative AI website traffic. By the one-month-ago snapshot it had reached 27.3% - an increase of 18.4 percentage points over the period.

The trajectory, month by month, is striking. Six months ago Gemini held 20.3%. Three months ago it reached 25.5%. One month ago it stood at 27.3%. Each data point represents an acceleration that compounds the competitive pressure on OpenAI. In proportional terms, Gemini's traffic share more than tripled over twelve months.

The questions this data raises for the marketing and media buying community are not trivial. As PPC Land noted when Gemini passed 22% in January 2026, the platform's growth creates direct implications for GEO and AEO strategies - the optimization disciplines that govern whether brand content surfaces inside AI-generated answers. A platform commanding more than a quarter of global AI traffic demands serious attention from anyone managing organic or paid visibility.

One methodological question circulated in the comments under Similarweb's LinkedIn post: whether Gemini's traffic figures incorporate Google's AI Mode and AI Overviews surfaces, or whether they represent only visits to the Gemini chat application specifically. Similarweb described the dataset as covering generative AI website traffic worldwide, which implies direct visits to AI platform domains rather than AI-generated answer surfaces embedded within search results pages. The distinction matters because AI Mode usage, if included, would substantially inflate Gemini's count. If excluded, the 27.3% figure represents Gemini's standalone chat product - and makes the growth even more remarkable.

Claude's 2.9-point jump: the fastest riser in the latest period

The most commented-upon finding in Similarweb's June update was not the top two platforms but the third-place mover: Anthropic's Claude. One month ago Claude held 6.0% of global generative AI traffic. By May 26, it had reached 8.9% - a gain of 2.9 percentage points in a single month.

Darren Goldstein, a Senior Growth Marketing Manager, noted in comments on the Similarweb LinkedIn post that Claude had become the fastest riser in the latest period, gaining 2.9 percentage points ahead of Gemini's 1.8-point increase over the same interval. Twelve months ago Claude held just 1.6%. At 8.9% today, the platform has multiplied its traffic share more than fivefold over the year.

This trajectory aligns with independent measurement from other sources. Comscore's March 2026 Consumer AI Chatbot Usage Rankings, reported by PPC Land on May 26, documented Claude expanding 130.1% from February to March 2026, reaching 2.66 million U.S. desktop unique visitors. That figure moved Claude firmly into fourth place among the platforms Comscore tracked - though it is worth noting that Comscore measures U.S. desktop unique visitors while Similarweb's traffic share data covers worldwide all-device website traffic. The two methodologies are not directly comparable, but both point in the same direction.

The pace of Claude's growth carries implications beyond brand sentiment. Platforms that attract a rapidly growing share of AI-mediated queries become more relevant surfaces for GEO optimization - the discipline of improving the likelihood that AI systems will cite a brand or retrieve content when generating answers. As PPC Land has covered since at least July 2025, Similarweb itself has built product infrastructure specifically to help marketers track their visibility and referral traffic across AI platforms including Claude.

DeepSeek, Grok, Copilot, and Perplexity

The remaining four platforms tracked in Similarweb's update show a more complex picture, with some gaining and others losing ground over the period.

DeepSeek held 5.3% twelve months ago and sits at 4.0% in the most recent data - after reaching a brief high of 3.8% six months back, the platform has recovered to 4.0%, though the twelve-month comparison shows a modest net loss. The Chinese-developed model attracted significant Western attention in early 2025, and the data suggests a sustained but somewhat diminished presence.

Grok, developed by xAI, stood at 2.8% twelve months ago, reached 3.8% six months ago alongside DeepSeek, pulled back to 3.7% three months ago, and now sits at 2.8% - returning to where it started a year ago. PPC Land documented Grok overtaking DeepSeek for the first time in January 2026, when xAI's platform reached 3.5% against DeepSeek's 3.3%. That advantage appears to have compressed by May.

Microsoft Copilot has moved in a narrow band: 1.9% twelve months ago, 1.8% six months ago, 2.0% three months ago, and 2.0% one month ago. The platform's stability is notable given Microsoft's extensive distribution advantages through Windows and Office integrations. Copilot's inability to meaningfully expand its share despite those distribution levers suggests the product has not yet found a usage pattern that converts installed base into consistent AI platform visits.

Perplexity ran at 1.8% twelve months ago and has drifted slightly lower, reaching 1.3% in the most recent reading. The platform has consistently generated attention for its citation-heavy search approach, and PPC Land reported in mid-2025 that Perplexity processed 780 million queries monthly. Its declining traffic share relative to rivals suggests that query volume and website traffic share do not always move together - a gap likely explained by heavy API and mobile usage not fully captured by website-level tracking.

What traffic share does not measure

A comment posted by Ofir Halfon, Global Partnerships and GTM leader, under Similarweb's LinkedIn post identifies an important limit of the dataset: "What this data doesn't show is intent quality by platform. Traffic share tells you where people go, it doesn't tell you what they're asking, how deep into the purchase journey they are, or which platform is driving the most commercial outcomes. Someone asking 'what are the best running shoes' is very different from someone asking 'compare On Cloudmonster and New Balance 1080'. Same category, completely different commercial value."

This is a relevant caveat for anyone interpreting the numbers through a media buying or conversion lens. Traffic share is a reach metric. It says nothing about the query types, the commercial intent, the session depth, or the downstream conversion rates associated with each platform. Research covered by PPC Land in November 2025 found that AI traffic converts at three times higher rates than traditional channels across more than 1,200 publisher and news websites. But that finding is an aggregate; it does not disaggregate by platform, and the mix of commercial versus informational queries likely varies significantly across ChatGPT, Gemini, Claude, and Perplexity.

The decentralisation argument

A separate comment from Chuks Wesley, a content strategist, makes a structural observation: "The traffic share is becoming more decentralised over time." The data supports this reading arithmetically. Twelve months ago, ChatGPT held 76.4% alone - a position approaching the kind of monopoly concentration that characterises early-phase platform markets. Today, the top three platforms collectively account for roughly 89% of tracked traffic, with that share distributed across ChatGPT at 52.7%, Gemini at 27.3%, and Claude at 8.9%. The remaining 11% is split across four platforms.

Decentralisation of this kind creates specific operational challenges for marketers who have built AI visibility strategies around a single platform. Similarweb's own product development has reflected this reality, with the company's GenAI Intelligence Toolkit - launched in July 2025 - designed to track brand visibility and referral traffic across multiple AI surfaces simultaneously rather than optimising for any single platform. As PPC Land reported in November 2025, Similarweb research found that citation sets change 50% monthly and that only 11% of citations overlap between major AI platforms - a finding that makes multi-platform tracking operationally necessary rather than optional.

Context: 12-month benchmarks and what shifted

The twelve-month progression captured in Similarweb's data maps onto a period of significant product releases and adoption events. ChatGPT's share stood at 76.4% in June 2025, around the time when PPC Land first began tracking AI traffic conversion advantages. By January 2026, the platform had fallen to 65.2% in six-month terms. Google's release of Gemini updates and expansion of AI integration into its search products accelerated Gemini's uptake through the latter months of 2025 and into 2026. Claude's growth curve steepened sharply through early 2026, which Anthropic's product expansion - including new API capabilities and enterprise integrations - likely contributed to.

The broader context for all these numbers is one that PPC Land's reporting on Datos' Q1 2026 State of Search reportmakes plain: AI tools collectively account for less than 2% of total desktop web visits in both the US and Europe. The traffic share figures Similarweb publishes measure the distribution of traffic among AI platforms themselves - not AI platforms' share of the total web. Both dimensions matter to marketers, but they answer different questions. The first shows which AI platform is winning the race for AI-mediated queries. The second shows how large a role AI-mediated queries play in total digital traffic overall.

Why this matters for the marketing community

For media buyers, agencies, and brand marketers, the shift documented in Similarweb's June update has practical consequences across at least three areas.

First, GEO strategy - the optimization of brand content to appear in AI-generated answers - now needs to weight platforms differently than it did twelve months ago. Claude's move from 1.6% to 8.9% means it is no longer a secondary concern. Gemini's 27.3% share makes it the second most important surface for visibility optimization, ahead of all other platforms by a considerable margin.

Second, attribution and measurement require updating. As PPC Land covered in August 2025, AI platforms are expanding beyond standalone chat interfaces into browser integrations and agentic workflows. Website traffic data from standalone domain visits may increasingly undercount actual AI-mediated touchpoints as these expansions mature.

Third, the question of commercial intent by platform - raised in the LinkedIn comment thread by Ofir Halfon - remains largely unanswered by traffic share data alone. Advertisers and publishers evaluating which AI surfaces deserve investment need richer signal than visit share alone. That gap represents both a measurement challenge and a product opportunity for analytics providers.

The Similarweb June update, based on data through May 26, 2026, covers worldwide all-device traffic to generative AI platform websites. It reflects twelve months of measurement across seven named platforms - ChatGPT, Gemini, DeepSeek, Grok, Claude, Perplexity, and Copilot - plus an "Other" category. The data was published on LinkedIn by Similarweb on June 11, 2026.

Timeline

  • June 2025 - ChatGPT holds 76.4% of global generative AI website traffic; Gemini at 8.9%; Claude at 1.6%, according to Similarweb.
  • July 28, 2025 - Similarweb launches GenAI Intelligence Toolkit combining AI brand visibility tracking with traffic measurement as AI platforms generate 1.1 billion referral visits in June 2025.
  • November 6, 2025 - Research shows AI traffic converts at 3x higher rates than traditional channels across more than 1,200 publisher and news websites.
  • November 12, 2025 - Similarweb publishes AI citation analysis framework showing citation sets change 50% monthly and only 11% overlap across major AI platforms.
  • December 2025 - ChatGPT falls to 66.8%; Gemini climbs to 19.5%, according to Similarweb.
  • December 22, 2025 - Similarweb releases November 2025 data showing ChatGPT maintains two-thirds U.S. market share despite a 35% traffic decline.
  • January 16, 2026 - ChatGPT drops to 64.6% as Gemini surges to 22%; Grok overtakes DeepSeek for the first time in Similarweb tracking.
  • January 2026 - Six-month snapshot in Similarweb data: ChatGPT at 65.2%, Gemini at 20.3%, DeepSeek and Grok both at 3.8%, Claude at 2.0%.
  • February 15, 2026 - Similarweb launches AI Studio for enterprise customers following beta expansion.
  • March 2026 - Three-month snapshot: ChatGPT at 56.7%, Gemini at 25.5%, Claude at 6.0%, Grok at 3.7%, DeepSeek at 3.4%.
  • April 27, 2026 - Datos Q1 2026 State of Search report shows AI tools collectively account for less than 2% of total desktop web visits in the US and Europe.
  • May 2026 - One-month snapshot: ChatGPT at 52.7%, Gemini at 27.3%, Claude at 8.9%, DeepSeek at 4.0%, Grok at 2.8%, Copilot at 2.0%, Perplexity at 1.3%.
  • May 18, 2026 - Comscore March 2026 AI Chatbot Rankings show Claude growing 130.1% month-over-month to 2.66 million U.S. desktop unique visitors.
  • May 26, 2026 - Similarweb publishes June update capturing twelve months of generative AI traffic share data through May 26, 2026; Claude records fastest monthly gain among tracked platforms.
  • June 11, 2026 - Similarweb posts the June update on LinkedIn, with full twelve-month comparison across ChatGPT, Gemini, DeepSeek, Grok, Claude, Perplexity, and Copilot, worldwide all-traffic.

Summary

Who: Similarweb, the web analytics platform with 91,644 LinkedIn followers, released the data. The platforms tracked are ChatGPT (OpenAI), Gemini (Google), DeepSeek, Grok (xAI), Claude (Anthropic), Perplexity, and Microsoft Copilot.

What: A twelve-month comparison of worldwide generative AI website traffic share, as of May 26, 2026, shows ChatGPT declining from 76.4% to 52.7%, Gemini rising from 8.9% to 27.3%, and Claude tripling from 1.6% to 8.9% - with Claude posting the largest month-over-month gain in the most recent period at 2.9 percentage points.

When: The data covers the twelve months to May 26, 2026. Similarweb published the June update on LinkedIn on June 11, 2026.

Where: The dataset covers all worldwide traffic to generative AI platform websites, across all device types.

Why: The data matters because it documents a structural shift in which AI platform users are choosing for their queries - with direct consequences for GEO, AEO, brand visibility optimization, and any media buying strategy that treats AI platforms as a discovery or conversion surface.