How do you calculate an Ad’s Click-Through Rate (CTR)?

Click-Through Rate (CTR) is a fundamental metric in advertising that measures the effectiveness of an ad. It is calculated by dividing the number of clicks an ad receives by the number of times it is shown (impressions), then typically multiplied by 100 to express it as a percentage. Therefore, "Ad Unit Clicks/Impressions" accurately represents this calculation. "Impressions/Ad Unit Clicks" is incorrect as it inverts the ratio, providing a meaningless value. "Navigations/Ad Unit Clicks" is incorrect because navigations are a specific action taken after a click, not the primary measure of an ad's initial engagement rate.