What is Clickthrough Rate (CTR)? / Digital Marketing / By Claire Clickthrough rate is “A ratio showing how often people who see your ad end up clicking it. ” (Google) To calculate CTR we use a simple formula:Clicks ÷ Impressions = CTRCTR can be used to determine whether people are finding your ads relevant and useful – a high CTR is a good indication of a useful and relevant ad.CTR can be used to evaluate the success of your ads and keywords and is indicative of which ads need to be improved. Source: Actual cost-per-click: Definition