CTOR is click-to-open rate, a metric comparing clicks to opens instead of total delivered emails. A common calculation is: (Unique clicks ÷ unique opens) × 100.
In practical email marketing work, the important question is not just what CTOR means, but how it should influence decisions. It matters because email is one of the few channels a business can own directly. Strong email fundamentals improve trust, deliverability, segmentation, and long-term lead nurturing.
A strong approach should connect CTOR to measurable outcomes such as qualified traffic, calls, form submissions, booked appointments, ecommerce revenue, or lower acquisition costs.
Example
Example: If 800 subscribers open a campaign and 96 click a link, CTOR is 12%. A strong CTOR usually means the body content delivered on the promise of the subject line.