Definition

Click-to-open rate is the share of people who opened an email and then clicked a link inside it. It measures how well the content performed with the readers who actually saw it.

Open rate judges the subject line. Click-to-open rate judges the body: the writing, the layout and the call to action. Because it ignores people who never opened, it is a cleaner test of content than the plain click rate. It is not perfect, since open counts themselves are fuzzy, but it is useful for comparing two emails sent to similar lists.

A B2B example: two product update emails get similar open rates, but one has a much higher click-to-open rate. The team looks at the difference and finds the stronger email put its single link near the top with a clear reason to click.

Why it matters for B2B email

B2B emails often ask a busy reader to do one specific thing. Click-to-open rate tells you whether the email made that thing easy and worth doing, separate from whether the subject line worked. It is the fastest way to learn what kind of body copy your list responds to, and a fair way to compare emails sent on different days.

Related terms

Open rate Open rate is the share of delivered emails that were opened.
Click rate Click rate is the share of delivered emails where someone clicked at least one link.
Call to action A call to action is the specific thing an email asks the reader to do next: book a call, download a guide, reply with an answer, register for an event.

Part of the B2B email marketing glossary. Last updated 2026-10-08.