CTOR (Click-to-Open Rate)
The percentage of people who opened your email and then actually clicked something — a truer read on content quality than open rate alone.
…A rising CTOR tells us the email content and offer are resonating, independent of how the subject line performed.…
What it means
Click-to-Open Rate (CTOR) measures the percentage of email openers who clicked a link inside the message, calculated as unique clicks divided by unique opens, times 100.
Because it isolates people who already opened the email, CTOR judges the body content and call-to-action on their own merits — separate from whether the subject line earned the open in the first place.
Isolates content from subject lines
CTOR strips out subject-line performance so you can judge the email body and offer on their own.
Pinpoints weak CTAs
A low CTOR with a healthy open rate usually means the call-to-action or layout needs work.
Improves testing decisions
It tells you whether to test subject lines or email content next.
DNA's Take: We use CTOR to diagnose exactly where an email is losing people — the subject line or the content — so testing time goes to the right fix instead of guesswork.
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