Engagement rate calculator

Which method should you use?

Engagement by followers is the number most brands ask for, because it is the one everybody can compute from the outside. Engagement by reach is the more useful number — it tells you how the people who actually saw a post responded — but only you can see it, so quote it alongside the follower figure rather than instead of it.

Whichever you publish, say which one it is. A rate quoted without its denominator is the kind of number that gets discounted on sight.