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  • Writer's pictureTom Kothman

A Subject Line Checklist

Updated: Apr 14, 2023

Assuming an email gets delivered AND the contact sees it, the first thing impacting the open rate is the subject line. Here's a quick checklist of things to consider as you build effective subject lines.

Length of Subject Line

  • Keep the subject line short – 7 words and 41 characters are optimal.

  • Use emojis to help your subject line stand out.

  • Make the subject line unique to the recipient.

  • Take the time to A/B test your subject lines.

  • Find the balance between trendy and personalized.

Word Choice in Subject Line

  • Power Words

  • Industry Keywords

  • Security

  • Simplicity

  • Engaging

Establish Urgency

  • Act Now

  • Limited-time offer

  • Instant savings

  • Save today

  • Deadline approaching

  • Limited number available

  • Time sensitive

  • Don’t miss this

  • Hurry

Create Curiosity [1]

  • Ask a curiosity-inducing question

  • Start a sequence of events, but don’t finish (e.g. an unfinished story)

  • Violate expectations

  • Imply that you have information they don’t

  • Imply that they used to know something that they’ve since forgotten

[1] Loewenstein, G. (1994). The psychology of curiosity: A review and reinterpretation. Psychological bulletin, 116(1), 75.


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