CTOR – Click-to-Open Rate

Definition

The Click-to-Open Rate (CTOR) measures the percentage of email recipients who open an email AND subsequently click a link. Unlike click rate (clicks / delivered emails), CTOR only relates to recipients who actually opened the email. This makes CTOR a purer indicator of email content quality – independent of the subject line.

Formula

Example

An email is opened by 500 recipients and 75 click a link. The CTOR is (75 / 500) × 100 = 15%. An average CTOR is 10-15%, good values are above 20%.

Optimization Tips

Optimize email content and CTA placement (since the subject line does not affect CTOR). Use clear, prominent buttons instead of text links. Personalize content based on user interests. Test different layouts and CTA copy.