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CTOR Calculator

Calculate your click-to-open rate (CTOR) to measure email content effectiveness. CTOR shows how well your email content drives clicks among subscribers who opened, with industry benchmarks and improvement tips.

Click-to-Open Rate (CTOR) Calculator

Measure how effectively your email content drives clicks among subscribers who opened

Number of unique subscribers who opened your email

Number of unique subscribers who clicked a link

CTR vs CTOR: What is the difference?

  • CTR (Click-Through Rate) = Unique Clicks / Emails Delivered — measures overall campaign effectiveness
  • CTOR (Click-to-Open Rate) = Unique Clicks / Unique Opens — measures content effectiveness among those who opened
  • A low CTR with a high CTOR means your content is great but your subject line needs work
  • A high CTR with a low CTOR means your subject line is strong but the email content underdelivers
  • CTOR is the best metric for evaluating email content quality independent of subject line performance

Note on Apple Mail Privacy

Apple Mail Privacy Protection (MPP) can inflate unique opens by pre-loading tracking pixels, which may artificially lower your CTOR. If a large portion of your subscribers use Apple Mail, consider focusing on CTR as a more reliable metric, or segment out Apple Mail users for a more accurate CTOR calculation.

About this tool

CTOR (Click-to-Open Rate) is the best metric for evaluating your email content quality, independent of subject line performance. While CTR measures overall campaign reach, CTOR isolates how effective your email body is at driving action among those who actually opened. This makes it invaluable for A/B testing email designs, CTA placements, and content strategies. Use alongside the open rate calculator (for subject line effectiveness) and CTR calculator (for overall reach). Note that Apple Mail Privacy Protection may inflate opens and artificially lower CTOR.

Frequently Asked Questions

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