CTOR

Click to Open Rate is CTR’s sharp­er sib­ling. Unlike CTR, which mea­sures clicks against all emails deliv­ered, CTOR only looks at peo­ple who actu­al­ly opened your email — then asks: of those, how many clicked? It’s cal­cu­lat­ed by divid­ing the num­ber of unique clicks by the num­ber of unique opens, and mul­ti­ply­ing the result by 100.

This makes CTOR a much more pre­cise mea­sure of con­tent qual­i­ty. A low CTOR means your email got opened but did­n’t deliv­er — the design, lay­out, copy, or CTAs need work. A high CTOR means that once peo­ple read your email, it con­vinced them to act.

If CTR tells you whether your emails are being engaged with, CTOR tells you whether they’re worth engag­ing with.