Key Event

A key event is any GA4 event you mark as important to your business, such as generate_lead after a contact form or purchase after a checkout. Until March 2024 these were called conversions in GA4. Google renamed them to key events so that “conversion” would mean the same thing in GA4 and Google Ads: an action used to measure and optimize ad performance.

Many guides, screenshots, and courses still say “mark as conversion”. The setting is the same; the label changed. In GA4 you open the Events list (or the Key events page in Admin) and toggle the event as a key event. GA4’s recommended events, such as generate_lead, sign_up, and purchase, are the easiest to use because their names and parameters are predefined.

A key event is still an ordinary event underneath. The event count shows how many times it fired; marking it as a key event adds it to key event reports and to engagement calculations, because any session with a key event counts as engaged.

What a key event is not: it is not automatically a Google Ads conversion. To use it for ad bidding, you import it into Google Ads, where it becomes a conversion action. That handoff is covered under conversion tracking.