What is a key event in GA4, and how is it different from a conversion?

GA4 records everything as events: page views, scrolls, clicks, video plays, purchases. Most are background activity. A key event is simply an event you flag as meaning something for the business. In the admin, under events, you switch on the 'mark as key event' option, and GA4 then reports how many times it happened and which channels, pages and campaigns led to it.

Until 2024 these were called conversions inside GA4. Google changed the name to key events to separate them from conversions in Google Ads, which are what Google's ad bidding optimises toward. You can import a GA4 key event into Google Ads as a conversion, and then it becomes both. The rename caused confusion because older guides and plugins still use the word conversion.

Choose key events that reflect real business outcomes. For a clinic in Islamabad: appointment form submitted, WhatsApp button clicked, phone number tapped. For an online store: purchase, and perhaps begin checkout. For a school: admission enquiry form submitted and prospectus downloaded. Avoid marking page views or scrolls as key events; they inflate the numbers and hide the actions that matter.

Some key events need setting up before they can be marked. Enhanced measurement captures some actions automatically, but a WhatsApp click or a thank-you page after a form usually needs a custom event through Google Tag Manager or a rule in GA4. Test each one by doing the action yourself and checking that it appears in the Realtime or DebugView report before trusting the totals.