Click-Through Rate is the percentage of users who click on an ad after seeing it. It is calculated by dividing the number of clicks by the number of ad impressions and multiplying by 100. For instance, if an ad gets 100 clicks out of 10,000 impressions, the CTR is 1 percent. CTR is a helpful indicator of how relevant or compelling an ad is to its audience. However, a high CTR does not always equal high performance. It must be evaluated alongside the quality of traffic and post-click outcomes like bounce rate, time on site, and conversions.