How to track ChatGPT referral traffic in GA4

Where does ChatGPT traffic show up in GA4?

ChatGPT traffic can land in four places in GA4, depending on whether the visit carries a referrer, a utm tag, both or neither. Visits with a recognized referrer now sit in the AI Assistant channel. Visits with only OpenAI's utm_source=chatgpt.com tag show that source. Visits with neither read as Direct, and phone calls never appear at all.

Google's Analytics Help 'What's new' page dated May 13, 2026 says matching sessions get the medium 'ai-assistant', the channel 'AI Assistant' and the campaign '(ai-assistant)', and the change applies going forward. Search Engine Journal's May 14, 2026 report notes Google has not published the full list of recognized assistants beyond ChatGPT, Gemini and Claude, so Perplexity and Copilot need checking in each property.

Why does so much ChatGPT traffic show as direct?

ChatGPT traffic shows as direct when the browser sends no referrer header and the link carries no utm tag. That happens most often in mobile apps, desktop apps and in-app browsers, and when a person copies a link rather than clicking it. GA4 has nothing to classify, so the session defaults to Direct.

The most quoted number is Loamly's. Marco Di Cesare's November 7, 2025 Loamly post estimated 60%, then a February 2026 update replaced it with measured data: 14,413 of 20,428 AI visits (70.6%) arrived with no referrer, across 446,405 visits. Loamly is a vendor and its method for spotting AI visits without a referrer has not been independently audited.

The number is also often quoted backwards. David Rosam's September 2026 newsletter points out that 70.6% is the share of AI visits missing a referrer, not the share of a firm's Direct traffic that is secretly AI; most Direct traffic is still genuine direct. Clickport's April 2026 snapshot, a self-selected sample, found 935 of 2,619 AI Search sessions (35.7%) carried source tags but no referrer, which is the slice OpenAI's utm tag rescues.

How do you set up GA4 to catch ChatGPT referrals?

Start with the AI Assistant channel GA4 now provides, then add a custom channel group for the assistants it may not recognize, and mark the consult form and click-to-call as key events. The setup takes under an hour in a typical property and changes nothing about how the firm's existing channels report.

• •1. Open Reports, Acquisition, Traffic acquisition with the Default Channel Group and confirm an AI Assistant row appears for sessions after May 13, 2026.
• •2. Under Admin, Data display, Channel groups, copy the default group and add a channel named AI Referrals with session source matching a regex such as chatgpt\.com|chat\.openai\.com|perplexity\.ai|gemini\.google\.com|copilot\.microsoft\.com|claude\.ai.
• •3. Move that channel above Referral, because GA4 assigns a session to the first rule it matches.
• •4. Add a filter for session source chatgpt.com so utm-tagged visits without a referrer are counted alongside referred ones.
• •5. Mark the consultation form submission and the click-to-call tap as key events, so the report shows consults per channel, not only sessions.
• •6. Each month, list Direct sessions that land on deep practice or FAQ pages. A typical person typing the URL lands on the homepage, so a rise in Direct entries to a page an engine cites is a signal worth noting, not proof.

How should a law firm count consultations that came from ChatGPT?

Count them at intake, because the consult is the outcome and analytics misses part of the path. Add 'ChatGPT or another AI assistant' as an option to the 'How did you hear about us?' question on the form and in the intake script, and pass utm values into the booking tool so a scheduled consult keeps its source.

Calendly's help center documents passing utm_source and the other utm parameters through an embed, including pulling them from the page URL, and the values then appear on the booked event and in webhook payloads. Phone intake needs the same question asked aloud, since a caller reading a number off an answer leaves no web trail.

Two constraints apply. Intake data is confidential under ABA Model Rule 1.6, so keep matter details out of URLs, event names and analytics parameters; the source is enough. And if the firm later publishes a claim such as a share of clients found through AI, ABA Model Rule 7.1 requires it to be truthful and not misleading, so the firm's ethics counsel should see the method before the number goes on a page. In Quebec, consent-gated analytics under Law 25 will undercount further, which makes the intake question more important there.

What does the GA4 number actually tell a law firm?

The GA4 number is a floor on clicks, and clicks are a small share of law firm traffic today. Great Jakes reported AI referrals at 0.47% of sessions across its law firm client portfolio in May 2026, and Martindale-Avvo put AI tools under 5% of total law firm website traffic in April 2026. Read movement in the trend, not the level.

ChatGPT dominates what is measurable. Previsible's July 6, 2026 report, across 166 properties and 6.77 million AI sessions, found ChatGPT sent 92.4% of standalone assistant referrals, so a firm that gets ChatGPT right in GA4 has most of the visible channel covered. The monthly reconciliation below is Firm AEO's working routine, not a published standard:

• •AI Assistant channel sessions and key events, month over month.
• •Session source chatgpt.com sessions not already in that channel.
• •Direct entries to the practice pages the firm's mention ledger shows engines citing.
• •Intake answers naming an AI assistant, from forms, Calendly and phone.
• •The share of answers from the logged-out prompt ledger, which says whether a click was even possible.