The Click to Open stat is simply calculated by dividing the number of people who click by the number of people who open is essentially comparing the number of unique clicks to unique opens. This rate can indicate how engaging the email is and whether it sparked enough interest in the recipient to not only open it but to click as well. This stat provides insights into the engagement and relevance of your content in your newsletter.
A good Click to Open rate is considered to be 6-17% according to Campaign Monitor. Check out this to discover Click to Open Rate benchmarks by industry.