Active Users

Active Users is the count of distinct people who had at least one engaged session in the period you selected.

This is GA4's headline user number. When a report or the top of a card just says "Users," it means Active Users. A person counts once no matter how many times they visited, and they only count if they engaged at least once, so a visitor who bounced off instantly does not show up here.

Say 1,000 people land on your site over a week. 720 of them either stay past ten seconds, view a second page, or trigger a key event. Your Active Users for that week is 720, not 1,000. The other 280 sit in Total Users but never make it into the metric almost every report defaults to.

Active Users is not Total Users, and the gap trips people up constantly. Total Users counts everyone who fired any event; Active Users filters that down to people who engaged. If your Universal Analytics "Users" number looks like it dropped when you moved to GA4, this is usually why. You are comparing two different definitions, not watching traffic fall.

If it says Users in GA4, it means active ones.