Bounce Rate vs Engagement Rate: What's the Difference?

Bounce rate, in the classic Universal Analytics sense, was the percentage of single-page sessions with no interaction - someone who landed and left without triggering another hit. Lower was always better.

Engagement rate is GA4's replacement metric: the percentage of sessions that were "engaged," meaning the session lasted 10 seconds or longer, included two or more pageviews, or included a conversion event. GA4 does still report a bounce rate, but it's defined as the inverse of engagement rate - a non-engaged session - rather than the old single-page definition.

The practical confusion happens when comparing historical Universal Analytics bounce rate against GA4's version - they aren't measuring the same thing, so a "bounce rate went up" comparison across the two platforms is usually meaningless. Engagement rate is the more useful metric going forward because it captures genuine interaction rather than just page count, but like any single metric it should be read alongside what the page is actually meant to do - a single-page resource that fully answers someone's question can have a low engagement rate and still have done its job.