In one line
Interactions as a percentage of followers, reach or views, depending on the formula used.
A creator with 20,000 followers averages 600 likes and comments a post: by followers, an engagement rate of 3%. Divided by reach or by views instead, the same post gives a different figure.
Rates worked out on different bases cannot be compared. Ask which formula and which posts a figure uses.
Agree: the formula, the posts it covers and the period, written next to the figure. Work one out with the free calculator at /tools/engagement-rate-calculator.
