Definition
Click-through rate (CTR) is the share of people who clicked a link after seeing it, in an ad, a search result, an email or an in-app message.
Formula
CTR = clicks ÷ impressions × 100.
Example
An email delivered to 5,000 people and clicked by 150 has a CTR of 3%.
Reading it
CTR measures how well a message earns attention, not whether the visit was worth anything. A high CTR with poor conversion means the message promised something the page didn't deliver. Follow clicks through with UTM parameters and judge channels on the sign-ups and retained customers they bring.