# Click through rate (CTR)

Source: https://joinbreaker.ai/newsletter-glossary/click-through-rate

CTR, or click through rate, is a metric that measures the effectiveness of an email by calculating the percentage of recipients who clicked on one or more links contained in an email, leading them to a website.

It's important to note that many ESPs have different definitions for CTR. Some represent CTR as the "[click rate](/newsletter-glossary/click-rate)" (where recipients is the denominator), while others represent CTR as what the industry generally refers to as the "click-to-open rate" (where opens is the denominator). Both of these numbers have different implications for performance, and for that reason Breaker displays both click rate and CTOR in reporting.