CTR (Click-Through Rate) is a key metric in digital marketing that measures how often people click on an ad or a link compared to how many times it was shown. It helps assess the effectiveness of an online advertising campaign or email marketing efforts.

Formula:
CTR = (Total Clicks / Total Impressions) × 100%

Explanation:
Total Clicks is the number of times users clicked on the ad or link.
Total Impressions is the number of times the ad or link was displayed.
For example, if an ad received 200 clicks and was shown 10,000 times (impressions), the CTR would be:
CTR = (200 / 10,000) × 100 = 2%

This means 2% of people who saw the ad clicked on it.