Glossary
Click-to-open rate (CTOR)
Unique clicks divided by unique opens: how many of the people who opened also clicked.
ValidReach Team · Updated 2026-10-26
In practice
It judges content among readers, separate from the subject line that earned the open. Open tracking is unreliable, because some mail apps preload images and register an open the reader never made, so treat CTOR as a rough guide.
Example
60 clicks from 600 opens is a CTOR of 10%.
Verification and sending
Not a verification measure, but invalid addresses never open, so they do not distort CTOR the way they distort click rate.