CTOR stands for which term?

• A. Click-To-Open Rate.
• B. Click-Through Rate.
• C. Conversion-To-Open Rate.
• D. Click-Open Rate.

Answer: (A)

CTOR is the Click-To-Open Rate, a metric that reveals how compelling the email content is to people who have already opened it. It’s calculated as the number of unique clicks divided by the number of unique opens, usually shown as a percentage. This focuses on post-open engagement: how many recipients who opened the email went on to click a link. It helps you judge content relevance independent of how many people even opened the email.

This differs from Click-Through Rate, which measures clicks relative to the total number of delivered messages, capturing overall engagement from send to click and including those who never opened. So CTOR specifically looks at opens as the base, while CTR looks at the broader audience. Other terms like Conversion-To-Open Rate or Click-Open Rate aren’t standard labels for this metric; CTOR remains the standard shorthand for clicks divided by opens.

Example: if 100 people open the email and 20 click a link, CTOR = 20/100 = 20%.