You might have noticed growing traffic from ChatGPT in your Google Analytics.

You can usually see it in GA by filtering Source as chatgpt.com and Medium / Channel Grouping as Referral.

However, that number is likely much smaller than the real traffic figure.

Why Google Analytics under‑reports ChatGPT traffic

Reason 1: ChatGPT link clicks don’t always show as Referral

Even though in Google Analytics the Source will still be chatgpt.com, the Medium / Channel Grouping might be Unassigned or not set. This usually happens when the ChatGPT link has no UTM parameters—common for linked mentions within ChatGPT answers.

In your report, focus on Source and don't filter on Medium or Channel Grouping.

Reason 2: Most ChatGPT visits come through Organic Search or Direct

First, if the user clicks a link in the ChatGPT answer from the mobile app, it opens in the phone’s browser (Safari, Chrome, etc.) and doesn’t always send a referrer header, marking the Medium / Channel Grouping as Direct and the Source as (direct).

Second—and even more important—most ChatGPT answers list brand names but omit the hyperlink. If the user wants to visit that brand’s website but there is no link, they will either:

• Type the brand URL directly into the browser → GA4 records it as Direct.

• Google the brand and click the first result → GA4 records it as Organic Search.

All these paths hide the ChatGPT source that started the journey, so the visible “AI share” of traffic is smaller than reality.

More traffic, more sign‑ups

On top of all that hidden ChatGPT traffic, engagement and conversions from that traffic are higher [1]:

• Average session duration: 10.4 minutes vs. 8.1 minutes for Google traffic.

• Average pages viewed: 12.4 pages vs. 11.8 pages for Google traffic.

• Higher conversions than most channels.

This means your ChatGPT share of total sign‑ups is much higher than its share of traffic. Companies like Tally have reported that 25 % of all new sign‑ups come from ChatGPT—an impressive jump for a non-existent channel three years ago.

A simple way to measure this this is to ask users at sign‑up “How did you hear about us?” with a dropdown menu. You'll see that the ChatGPT share of sign‑ups is likely far higher than its share of GA traffic.

Citations

[1] https://www.growth‑memo.com/p/the-state-of-ai-chatbots-and-seo