Conversion Rate

Conversion rate in GA4 is the share of users or sessions that included a key event, depending on which version you read.

GA4 renamed conversions to key events, so this is really key event rate. There are two flavors. User conversion rate is the percentage of active users who triggered a key event; session conversion rate is the percentage of sessions that did. GA4 shows both, and they answer different questions, so you need to know which one is on screen.

1,000 active users produce 1,400 sessions, and 70 of those sessions include a purchase key event. Your session conversion rate is 5 percent. But if those 70 purchases came from 60 distinct people, your user conversion rate is 6 percent. Same purchases, two different denominators, two different numbers.

User rate and session rate are not interchangeable, and reporting the wrong one misleads. User conversion rate runs higher than session rate whenever people take more than one session to convert, which is most considered purchases. Decide upfront whether you are measuring people or visits, label it, and stay consistent. Do not quote one number this month and the other next month.

Same conversions, two denominators. Know which one you are showing.