Engagement rate is a performance metrics that expresses the proportion of viewers who actively interact with a video — through likes / reactions, comments, shares, or saves — relative to total views or impressions. On YouTube, a healthy engagement rate signals to the algorithm that an audience finds the content compelling, which can positively influence distribution across Search, Home, and Suggested feeds. It is one of the most important indicators in benchmarking channel health, alongside retention rate and click-through rate (CTR).