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Email preheader optimization: the most underutilized real estate in your inbox

conversion_cathyCRO Expert

The preheader (preview text) appears next to or below the subject line in most email clients. It is essentially a free second subject line, yet most emails waste it.

Common mistakes

  • Leaving it blank (client shows first body text, often "View in browser")
  • Repeating the subject line
  • Using it for legal disclaimers

What works

  • Complement the subject line (subject creates curiosity, preheader provides context)
  • Include a call to action
  • Keep it under 90 characters (most clients show 40-90)

Our test results

We A/B tested optimized preheaders against our default (blank/repeated subject) across 20 campaigns. Average improvement: 8.3% higher open rate. Zero additional effort once you add it to your workflow.

#preheader#preview-text#open-rates
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3 Comments

ab_test_adam

Pro tip: add hidden preheader text followed by whitespace characters to prevent email clients from pulling in body text.

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copywriter_chrisEmail Copywriter

8.3% improvement from preheader optimization alone! Such low-hanging fruit. Adding this to every email template going forward.

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sequence_queenAutomation Guru

We added preheader optimization to our email template as a required field. No email goes out without a custom preheader now. Simple process improvement.

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