The engagement rate shows how well the creator connects with their audience. It takes into account the number of followers and their interactions with recent posts.
The Engagement Rate calculation is based on the last 2 months with the following formulae -
TikTok & Youtube: Average Likes / Average Views
Instagram: Median Likes / Followers
In the past, followers were a good proxy for understanding how many people a creator could reach. The content they posted was mostly displayed to their followers.
Today, however, content is purely served based on recommendations or through the famous "For You" page. This means the number of views somebody gets for the content is far more telling than the followers.