Click-to-open rate (CTOR)
The percentage of tracked email openers who clicked, commonly calculated as unique clickers divided by unique opens.
Click-to-open rate, or CTOR, compares unique clickers with tracked unique opens, multiplied by 100. For example, 20 clickers and 200 recorded openers produce a CTOR of 10%. Check your provider’s definition before comparing reports.
CTR instead compares clicks with sent or delivered emails. If the same email reached 1,000 recipients, its unique click rate would be 2%. Both calculations can describe the same send without contradicting each other.
CTOR does not isolate content quality. Automated opens, image blocking, and bot clicks can distort either side of the fraction. Use it as a qualified comparison within a consistent reporting setup, not a precise count of readers persuaded by the message.
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