Click-to-Open Rate (CTOR)

Click-to-open rate (CTOR) is the percentage of people who opened an email and then clicked a link within it. It is calculated by dividing unique clicks by unique opens. Unlike click-through rate (CTR), which measures clicks against total emails delivered, CTOR isolates the performance of your email content by only counting people who actually saw it.

CTOR matters in GTM operations because it separates subject line performance from email body performance. If your open rate is high but your CTOR is low, the subject line did its job but the email content failed to compel action. If both open rate and CTOR are high, you have a well-performing email end to end. This distinction helps you diagnose exactly where to focus optimization efforts.

A typical B2B email CTOR ranges from 10-20%, though this varies significantly by email type. Transactional emails and highly targeted nurture emails tend to have higher CTORs than broad newsletter blasts.

For example, suppose you send a product launch email to 10,000 contacts. 2,500 open it (25% open rate) and 400 click the CTA (16% CTOR). If you then A/B test two different email body layouts and one achieves a 22% CTOR while the other stays at 16%, you know the new layout significantly improved content engagement — independent of subject line performance.

CTOR is especially useful for comparing email content across campaigns with different audiences or send times, since it normalizes for open rate differences. Marketing teams tracking email performance through analytics dashboards should include CTOR alongside open rate and CTR to get a complete picture of email effectiveness.