- ChatGPT dominates every dataset reviewed for this piece, but by different magnitudes depending on what's being measured. SE Ranking's referral-traffic data puts it at 74.78% of AI referral traffic; Similarweb's total-visit-share measure puts it at 52.7%, down sharply from 76.4% a year earlier.
- SE Ranking and Similarweb are measuring genuinely different things: referral traffic sent to other sites versus each platform's own total visit share within the generative-AI category. Neither figure is wrong; they're not directly comparable, and conflating them produces a misleading picture.
- Gemini's share grew substantially in both datasets, more than tripling in Similarweb's total-visit measure, though it's unclear whether that figure folds in Google's separately-branded AI Overviews and AI Mode traffic.
- Claude accounts for the smallest referral-traffic share of the five platforms SE Ranking tracked (2.62%), consistent with the lower overall citation rate already documented for Claude elsewhere on this site.
- A lower-confidence source reports different numbers still (ChatGPT at 55-60%, Perplexity at 18-22%), without disclosed methodology, underscoring that "which platform drives the most traffic" doesn't have one clean, universally agreed answer even among sources that are each individually disclosed.
Every source claiming to answer "which AI platform drives the most traffic" is measuring something slightly different, and the disagreement between the two most disclosed datasets available is itself the most honest finding here.
What does the referral-traffic data say?
SE Ranking's 2026 data, measuring AI referral traffic specifically (visits a website receives that originated from a given AI platform), ranks the platforms clearly: ChatGPT first at 74.78%, Gemini second at 11.56%, Perplexity third at 7.23%, Copilot fourth at 3.51%, and Claude fifth at 2.62%. That ranking is consistent with other platform-behavior data already on this site, including Claude's comparatively low citation rate against ChatGPT, which would plausibly translate into a lower referral share too.
Is ChatGPT's dominance actually shrinking?
By one measure, modestly; by another, sharply, and the gap between those two answers is the real finding. SE Ranking's own data shows ChatGPT's referral-traffic share falling from 79.74% a year earlier to 74.78%, while its raw referral traffic volume still grew roughly 27% year over year in absolute terms, meaning the AI-referral pie overall is growing fast enough that ChatGPT keeps growing in absolute numbers even as its relative share erodes slightly. Similarweb's separate measure, tracking each platform's total website-visit share within the broader generative-AI category (via PPC Land's coverage of a June 2026 Similarweb update), shows a considerably sharper decline: from 76.4% of total generative-AI website traffic twelve months earlier down to 52.7% by May 26, 2026, with Gemini's own share more than tripling over that same period.
Why do these two numbers disagree so much?
Because they're not measuring the same thing, and treating them as interchangeable is where most of the confusion in this space comes from. SE Ranking's figures describe referral traffic: visits a third-party website receives as a result of an AI platform sending a user there. Similarweb's figures describe something closer to the platforms' own market share: total visits to each AI platform's own site or app, within the generative-AI category overall, independent of whether those visits then result in a referral click to anywhere else. A platform could plausibly gain overall usage share (more people visiting it) while sending a stable or even shrinking share of referral clicks elsewhere, if its own answers are getting more self-contained. The coverage of Similarweb's numbers explicitly flags one more wrinkle: it's unclear whether Similarweb's Gemini figure folds in Google's separately-branded AI Overviews and AI Mode traffic, which would make the Gemini comparison even less apples-to-apples against SE Ranking's Gemini referral figure.
How reliable is any single number in this space?
Treat it with real caution regardless of source. A third, lower-confidence source reports yet another set of figures (ChatGPT at 55-60% of AI-chatbot referrals, Perplexity at 18-22%) without disclosed methodology behind either number, which is worth flagging precisely because it shows how much variance exists even among sources that each present their own figures as settled. SE Ranking's and Similarweb's data are individually the most disclosed and specific sources found in researching this piece, but they measure different things and shouldn't be blended into one number.
What's the practical takeaway?
ChatGPT is the dominant referral source by every disclosed dataset reviewed here, by a wide enough margin that it should be the first platform any AI-visibility measurement effort covers. Gemini is the clearest second-place story and the platform showing the most consistent growth across both referral-traffic and total-visit measures. Claude and Copilot remain small referral sources today by SE Ranking's data, which doesn't mean ignore them (their measured conversion rates on referred traffic run meaningfully higher than their traffic volume alone would suggest) but does mean calibrate expectations for raw visit counts accordingly.
Frequently asked questions
Which AI platform sends the most referral traffic to websites?
ChatGPT, by a wide margin in every dataset reviewed for this piece, though the exact share and trend direction differ by source. SE Ranking's 2026 referral-traffic data puts ChatGPT at 74.78% of all AI referral traffic, with Gemini second at 11.56%, Perplexity third at 7.23%, Copilot fourth at 3.51%, and Claude fifth at 2.62%.
Is ChatGPT's dominance growing or shrinking?
Both, depending on which metric you look at, and that's the genuinely useful finding here. SE Ranking's referral-share data shows ChatGPT's share falling from 79.74% to 74.78% year over year, while its raw referral traffic volume still grew about 27% in the same period. A separate measure, total website-visit share from Similarweb, shows a much sharper decline, from 76.4% to 52.7% over roughly the same window.
Why do SE Ranking's and Similarweb's numbers disagree so much?
They measure different things. SE Ranking's figures describe referral traffic specifically, meaning visits a website receives that originated from an AI platform. Similarweb's figures describe each platform's own total website-visit share within the broader generative-AI category, a measure of the platforms' own popularity, not of the traffic they send elsewhere. The two aren't directly comparable, and it's also unclear whether Similarweb's Gemini figure includes Google's separate AI Overviews and AI Mode traffic.
Is Claude a meaningful source of referral traffic?
Not currently, by SE Ranking's data: Claude accounts for only 2.62% of AI referral traffic, the smallest share of the five platforms SE Ranking tracked, consistent with Claude's own lower citation rate relative to ChatGPT already covered elsewhere on this site. One source claims Claude has recently tripled its AI traffic share, though that specific figure wasn't independently corroborated in researching this piece.
Sources referenced
- SE Ranking: AI traffic grew 16x from 2024 to 2026
- PPC Land: ChatGPT drops to 52.7% as Claude triples its AI traffic share (citing Similarweb data, June 2026)
For the conversion-rate data behind why smaller-traffic platforms like Copilot still matter, see AI visibility ROI. For why Claude's referral share is this small, see how Claude's citation behavior differs from other models.
