Conversion rate is the percentage of total users who complete a desired action. The desired action is mostly purchase or lead form submitted, trial signed up, demo booked, etc. Conversion rate = (total number of conversions/ total number of visitors) x 100 With respect to ad platforms, it is the total number of conversions, to the total number of clicks on the ad. For example, if 1000 users click on your ad for purchasing a shoe, and 50 users only purchase (desired goal) out of 1000, then the conversion rate is calculated as = (50/1000)x100 = 5%