What is a key event in GA4?
GA4 records everything as events: page views, scrolls, clicks, form starts. A key event is any event you mark as important to your business. Google Analytics used to call these conversions; it now calls them key events, and uses the word conversion for the Google Ads conversions you create from them.
For a lead generation site, the key events are the actions that mean a prospect asked to talk to you. Everything else is supporting data.
Which events should a lead generation site track?
Keep the list short. Each key event should correspond to a real person reaching out.
- Form submitted: estimate requests, contact forms, booking forms. Google lists generate_lead as a recommended event for when someone submits a form or requests information.
- Phone call from the site: a click on a tel: link, ideally combined with call tracking that confirms the call connected.
- Chat or WhatsApp started: when a visitor opens a conversation from the site.
- Booking confirmed: if you use an online scheduler that can send an event or redirect to a confirmation page.
What not to mark as a key event
- page_view, unless it is a new event that only fires on a confirmation page.
- Clicks on a form's submit button, which fire even when validation fails.
- Scrolls, time on page or video views. They are useful signals, not leads.
How do you track form submissions in GA4?
There are three common methods. Pick the one that matches how your form behaves after a successful submit.
1. Thank-you page
If the form redirects to a confirmation page such as /thank-you, create a new event in GA4 based on page_view with a condition on that page's URL. Google's help on creating events explains why: if you marked page_view itself, every page view would count as a key event. The new event fires only on the confirmation page, and you mark that one.
2. Data layer event from the site
If the form shows a success message without changing the URL, which is common in React and other single-page apps, have the site push an event such as generate_lead to the data layer only after the server confirms the submission. Then send it to GA4 with a Google Tag Manager tag or directly with gtag. This is the most reliable method because it fires on real success.
3. Tag Manager form trigger
Tag Manager has a form submission trigger. It is quick to set up but can miss submissions or count failed ones, depending on how the form is built. Use it only after testing that it fires once per real submission.
How do you mark an event as a key event?
Once the event shows up in GA4, which can take up to a day for new events, mark it as a key event.
- Go to Admin, then Data display, then Events.
- Find the event, such as generate_lead or your thank-you page event.
- Turn on the option to mark it as a key event.
- Optionally set a default value and counting method. Counting once per session avoids double counting a visitor who submits two forms.
Adding a value
If you want to assign a value to leads, send a value parameter with a currency parameter. Google requires both: the value must be a number and must come with a currency. Use a conservative estimate of what a lead is worth to you, not the full job price.
How do you import GA4 conversions into Google Ads?
Google Ads can create conversions based on GA4 key events, so both tools use the same definition of a lead. Google's help lists the requirements and steps:
- Link your Google Analytics property to your Google Ads account.
- Turn on auto-tagging in Google Ads.
- Make sure you have the access level Google requires in both accounts.
- In Google Analytics, go to Advertising, then Conversion management under Tools, and create a new conversion.
- Select the Google Ads account and the key events to use, choose a category such as Submit lead form, then review and save.
Primary or secondary
In Google Ads, decide which conversions are primary, meaning bidding uses them, and which are secondary, meaning you only observe them. If Google Ads already has its own tag for the same form, do not make both primary, or every lead counts twice.
Where the numbers show up
Google notes that Google Ads conversions do not appear in standard GA4 reports. You see them in Google Ads and in the Advertising section of Google Analytics. Small differences between the two tools are normal because they attribute credit differently.
How do you test that tracking works?
- Submit a test form yourself and watch it arrive in GA4 DebugView or Realtime.
- Check that it fires once, not twice, and does not fire when the form shows an error.
- Call from the site on a phone and confirm the call event and, if you use it, call tracking.
- Compare a week of key events with the leads in your inbox or CRM. They should be close.
- After importing, check the conversion status in Google Ads over the following days.
Why does GA4 conversion tracking matter so much?
Smart bidding in Google Ads learns from your conversions. If the conversion is a page view or a button click, the system will find more of those, not more customers. Clean tracking is what lets automated bidding work for you, and what lets you compare channels honestly.
The next step after website events is offline data: marking which leads became estimates and jobs, and sending that back. That is how you move from cost per lead to cost per job.