Engagement Rate

Engagement rate measures interactions (likes, comments, shares, saves, or GA4 engaged sessions) relative to reach or impressions.

The formula and even the included actions vary by platform and by context — a social media engagement rate (likes + comments + shares ÷ reach or followers) is a completely different calculation from GA4's engagement rate (engaged sessions ÷ total sessions). Treat "engagement rate" as a category of metrics, not one metric, and always check what's in the numerator before comparing two engagement rates.

High engagement doesn't guarantee business value — a meme-style ad can rack up comments and shares from people who were never in-market, while a plain, unglamorous product demo with lower engagement quietly drives the actual sales.