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Guide 176 · Conversions · GA4 + Tag Manager

Mark a key event through Tag Manager: the GA4 event tag, then the star in GA4

Checked 11 November 2026 · Verification: key-event reference validated structurally (9 checks, all passed) · Steps traced to Analytics Help, read 11 November 2026 · 5-minute read

Tag Manager does not mark key events. It sends the event, and GA4 marks it. The two jobs live in two tools, and mixing them up is the most common failure in this section. This guide sends a phone_click event from Tag Manager, confirms it in DebugView, marks it in GA4, and works out the count for the first week.

Expected signal

After the steps, the phone_click key event appears under the Key events tab in Admin, and the standard reports show it within a day. The worked example below gives the count and the rate to expect.

Download the reference: the phone_click key-event reference (JSON) (671 bytes, MD5 416e42556421530f6ed939f1d987a37e). It holds the event name, the counting method, the worked-example figures recomputed for this guide, and the checkpoints that prove the key event is recording. The figures in the file are the same figures shown on this page.

What you need

  • Editor access in the Tag Manager container, and Editor access or above in the GA4 property. The tag is built in one tool and marked in the other.
  • The Google tag already installed in the container, sending page_view. This guide adds a GA4 event tag beside it; it does not replace the Google tag.
  • A click trigger for the phone link. In this guide the trigger is a Click — All Elements trigger that fires when the clicked element's URL starts with tel:.

The trace

  1. Build the trigger in Tag Manager. In the workspace, go to Triggers, then New, and choose Click — All Elements. Set the trigger to fire on Some Clicks, where Click URL starts with tel:. Name it Click — Phone link and save it.
  2. Add a GA4 Event tag. Go to Tags, then New, and choose the GA4 Event tag type. Set the Measurement ID to the property's ID, the one that starts with G-, and the Event Name to phone_click. Event names are lowercase with underscores.
  3. Attach the trigger and save the tag. In Triggering, select the phone-link trigger from step 1. Save the tag. A tag with no trigger never fires, and a trigger with no tag fires nothing.
  4. Check it in Preview before you publish. Click Preview, connect the site, and click the phone number. The tag must appear under Tags Fired on the click event. If it sits under Tags Not Fired, the trigger condition did not match the link.
  5. Publish the container as a version. Click Submit, choose Publish and Create Version, and publish. Preview tests the workspace draft; only the published version reaches visitors.
  6. Confirm the event in DebugView, then mark it in GA4. Open DebugView in GA4, click the phone number, and watch phone_click arrive with its parameters. Then open Admin, then Data display, then Events, and click the star on the phone_click row. In the worked example the first week shows 58 key events from 1,900 sessions, which is a session key event rate of 58 / 1,900 = 3.05%.

Dead ends

DEAD END — MARKING THE EVENT BEFORE IT EXISTS. The star only appears on events the property has collected. Marking is step 6, after the tag is published and the event has fired at least once. Doing it first means staring at a table with no phone_click row.

DEAD END — A TRIGGER ON THE WRONG CLICK. A Click — Just Links trigger misses a phone number wrapped in a button, because the click lands on the button, not the link. All Elements catches the click wherever it lands inside the link, which is why this guide uses it.

DEAD END — PUBLISHING THE TAG AND FORGETTING THE STAR. A published tag sends an ordinary event. Until the star is clicked in GA4, phone_click never appears in key event reports, and the session key event rate never moves.

End state

The phone_click event is sent by Tag Manager and marked as a key event in GA4. The first week shows 58 key events from 1,900 sessions, against 211 phone-link clicks in Preview testing that never reached the reports because Preview is not live data.

FigureValue
Sessions in the first week1,900
Phone-link clicks in the week58
phone_click key events58
Session key event rate3.05%
Preview test clicks, not counted211

The rate is 58 / 1,900 = 3.05%, recomputed in Python 3 and rounded to two places. The 211 Preview clicks are test traffic and are excluded from the count. The figures are a worked example, not a real property.

Sources

Checked 11 November 2026. The click paths above are the ones in Google's help and Tag Manager help pages, read 11 November 2026. The GA4 Event tag and its trigger, Preview verification, publishing as a version, and marking in GA4 are as Google documents them, and the GA4 event tag is the documented tag type. No step in this guide was run inside a live Tag Manager container or a live Analytics property, because both need a Google sign-in and this site does not sign in as anyone. The figures on this page are a worked example recomputed in Python 3 with decimal arithmetic, not numbers from a real property. Google moves menu items without warning; if a path on this page no longer matches, the linked help page is the current map.