CTR stands for click-through rate and is a metric that indicates the percentage of users who click on a particular link or advert in relation to the total number of users who have seen that link or advert. CTR is often used in online marketing and web analytics to measure the effectiveness of advertising campaigns, email marketing or search engine optimisation (SEO).

A high CTR indicates that the content or offer is relevant and appealing to the target audience, while a low CTR may indicate that improvements need to be made to the advert, link or underlying offer.