This document explains how we compute the metrics in Typefully's Grow tab. You may find this useful if you are a Twitter power user and want to dig deeper.
Impressions
The number of times your tweets are viewed by someone on Twitter.
Engagements
It's the sum of all the engagements for your tweets (likes + retweets + replies + profile clicks + link clicks). It may differ from Twitter's reported engagement, as they also consider media views and opens (we don't have access to this info via the Twitter API).
Engagement Rate
Engagements / Impressions
It measures how much people enjoy your tweets.
Profile Conversion Rate
New followers / Profile visits
It's an approximate[1] measure of how effective your Twitter profile (pic + bio) converts visitors to followers.
It will be initially empty, as we need followers (tracked from the day you sign up) to compute this.
[1] we can only track visitors coming from tweets, so you may see 100% if you are getting followers from other places (e.g. direct link to profile, podcast mention, etc.)