GA4 key events are the events a property marks as its most important, and for a service business that means three: a form submit, a booking, and a tap on the phone number. Marking one is a setting rather than code, and Google caps a standard property at 30 key events, which makes the list a choice.
Every platform fact below comes from Google's own Analytics and Ads documentation, as of October 2026. Two of the three can be built without a developer. The third is worth being honest about: a browser sees a tap on a number, not a phone call.
What a key event is, and what it replaced
A key event is an event that measures an action particularly important to the business, in Google's own framing, and any event a property collects can be marked as one. Key events replaced the word conversions inside Analytics; conversions now means the Google Ads concept built on a key event.
Google's documentation sets the order out as event, then key event, then conversion. Analytics collects the event, marking it makes the reports count it, and creating a Google Ads conversion from it is what makes the action eligible for bidding in Ads. Three stages, one event.
The three key events a service business marks
Three events carry the whole measurement for a service business: a form submit, a completed booking, and a tap on the published phone number. Each marks the moment a stranger became a lead. Google's recommended event for the first is generate_lead, which its reference lists as firing when a user submits a form or a request for information.
| Key event | Event name | What fires it | What it cannot see |
|---|---|---|---|
| Form submit | generate_lead | A view of a confirmation page, or a form-submission trigger in Tag Manager | Whether the lead was real, or whether anyone replied to it |
| Booking confirmed | A custom event, named once | The confirmation screen the booking tool shows after a slot is held | A booking taken on the phone or at the counter |
| Phone tap | A custom event on the tel: link | The tap itself, on the device the visitor is holding | Whether the call connected, how long it ran, or whether anyone answered |
The phone row is the one to read twice. A tap is a strong signal of intent and a weak signal of outcome, and that gap is where a service business loses money.
Why scroll depth and outbound clicks do not belong on the list
Scroll and outbound click are already collected automatically by enhanced measurement, and marking either as a key event turns the key-event count into a traffic count. Google's enhanced measurement page says the scroll event is sent the first time a user reaches the bottom of a page, defined as the point where 90% of vertical depth becomes visible.
Reaching the bottom of a page is not a lead. A property with scroll marked reports hundreds of key events a month and still cannot say which landing page produced a call. Keep the automatic events for diagnosing a page, the key-event list for actions worth paying for.
How to mark one, and the two limits that force a choice
Marking an event happens in the Analytics interface rather than in code: open the Events report, use the three-dot menu on the event's row, and select Mark as key event. Google's help page says you need Editor or above at property level, and that a standard property can mark up to 30 events.
Two limits do the deciding. The cap is 30 for a standard property and 50 for Analytics 360, which sounds generous until a team marks every form separately. The second is time: Google says to allow up to 24 hours before a newly marked event shows in standard reports, and that marking does not change historic data. Nothing marked today backfills last month.
Setting up the three without a developer
Two of the three can be built from a page view. Google's own tutorial for setting up a key event uses a page_view on a confirmation URL, the cheapest route for any form or booking tool that lands the visitor on a thank-you page. The phone tap needs its own tag.
- Give each confirmation page a URL nothing else uses. One thank-you page shared by the contact form and the booking tool collapses two events into one row, and no report separates them afterwards.
- Prefer the documented event name. Google's recommended events page advises using a recommended name such as generate_lead where one fits, because the prebuilt reports read those names; the same page notes recommended events are not sent automatically, so somebody implements it.
- Send the phone tap from Tag Manager as its own event. Google's enhanced measurement page describes the automatic click event as covering links that lead away from the current domain, which is not a tap on a tel: link.
- Mark the event once and leave its name alone. A renamed event starts a new row, and the old row stops on the rename date.
Reading the landing page by key event report
The landing page report is where a key event turns into a decision. Google describes it as session-scoped, with the landing page dimension holding the page path and query string of the first pageview in a session, and the key events metric counting how often users triggered a key event, populated by marking rather than automatically.
Add Session source / medium as a secondary dimension and the report answers the question an owner actually has: which page people arrived on, where they came from, and how many of those sessions produced one of the three events. Google's help page names that dimension as the way to see traffic sources per landing page
Two readings to expect. A landing page showing (not set) means a session with no page_view event, per Google's documentation, which usually points at a tag firing late or not at all. A page with heavy sessions and no key events is not automatically bad: check the event is marked first.
A key event is not a Google Ads conversion
Marking a key event in Analytics does not give Google Ads something to bid on. Google's documentation says that Google Ads conversions created from Analytics key events appear in the Advertising section of Analytics and do not appear in standard Analytics reports.
That is why two people looking at one business disagree about the number. The standard reports count key events, the Ads account counts conversions, and the two are different populations by design. Google's help also notes that building an Ads conversion from a non-key event marks it as a key event automatically.
What this looks like when it runs
A key event list is one instrument, and on its own it reports a number nobody acts on. Mirastart builds the measurement and the handling together for Charlotte businesses: the booking system that records the source at first contact, the missed-call text-back behind the phone tap, and one screen reporting in booked jobs.
The three events get set up once, named to a written convention, and pointed at the same booking record the phone and the front counter write to, so a tap, a form and a walk-in land in one row instead of three dashboards. The screen shows booked jobs by landing page and source, in that unit rather than sessions.
Every account stays in your name, the Analytics property included, with Mirastart added as a user you can remove. Ongoing engagements start at $3,000 a month, flat rather than a share of ad spend. The online booking and repair-status software Quick Auto NC runs its bays on is ours, as is the live-availability booking here.
Sources
- Google Analytics Help, "[GA4] Key event" - Source of the definition used here: a key event is an event that measures an action particularly important to the success of the business, and any event a property collects can become one. Read via search result summary on October 8, 2026; support.google.com is blocked to direct fetches from this environment.
- Google Analytics Help, "Mark events as key events" - Source of the marking mechanics and both limits: the three-dot menu on an event row in the Events report, Editor or above at property level, up to 30 key events for standard properties and 50 for Analytics 360, up to 24 hours before a newly marked event appears in standard reports, no change to historic data, and the toggle that marks an event at creation. Read via search result summary on October 8, 2026.
- Google Analytics Help, "[GA4] Conversions vs. key events in Google Analytics" - Source of the event, key event, conversion order; of the statement that Google Ads conversions created from Analytics key events appear in the Advertising section and not in standard Analytics reports; and of the note that building an Ads conversion from a non-key event marks that event as a key event automatically. Read via search result summary on October 8, 2026. The page does not quantify any difference between the two counts, and none is claimed here.
- Google Analytics Help, "[GA4] Landing page report" - Source of the report's session scope, the landing page dimension being the page path and query string of the first pageview in a session, the key events metric being populated by marking an event rather than automatically, the Session source / medium secondary dimension, and (not set) appearing when a session has no page_view event. Read via search result summary on October 8, 2026.
- Google Analytics Help, "[GA4] Recommended events" - Source for generate_lead firing when a user submits a form or a request for information, for the advice to use a recommended event name rather than a custom one where one fits, and for the statement that recommended events are not sent automatically and must be implemented. Read via search result summary on October 8, 2026.
- Google Analytics Help, "[GA4] Enhanced measurement events" - Source for the scroll event being sent the first time a user reaches the bottom of a page, defined as the point where 90% of vertical depth becomes visible, and for the automatic click event covering links that lead away from the current domain. The page does not discuss tel: links; the inference that a phone tap needs its own tag is the writer's. Read via search result summary on October 8, 2026.
- Google Analytics Help, "[GA4] Tutorial: Set up a key event" - Source for building a key event from a page_view on a confirmation URL. Read via search result summary on October 8, 2026.