Most of the decision on whether an email will be opened is made in a single line: the subject line. No matter how good your content is, if the subject does not draw interest, the email stays unopened. In this article you will find how to write an effective subject line, what to avoid, and examples you can use.

Summary: A good subject line is short, clear, and intriguing; it honestly reflects the content. Stay away from all-caps, exaggeration, and spam-triggering words. Test to find the best subject.

The traits of a good subject line

  • Short and clear: Most people read their email on a phone; subjects that stay within 5-8 words look better.
  • A single idea: Let the subject carry one clear message and not tire the reader.
  • Curiosity or benefit: Either ask a question or promise a concrete benefit.
  • Honest: The subject must match the email\'s content exactly; otherwise you lose trust.
  • Personal: Where possible, use the recipient\'s name or a detail specific to them.

What to avoid when writing a subject line

  • Writing it all in CAPITAL LETTERS,
  • Consecutive exclamation marks (!!!),
  • Spam-triggering patterns like "Free", "Hurry", "You won",
  • Exaggerated promises that do not match the content,
  • Needlessly long subjects that contain multiple ideas.

These patterns both shake the reader\'s trust and increase the chance of your email landing in spam. On this topic, you can take a look at the preventing emails from landing in spam article.

Subject line examples

You can use the examples below by adapting them to your own brand and content:

Campaign / discount

  • "20% off just for you this week"
  • "The items in your cart before they run out..."
  • "Today only: new season deals"

Newsletter / content

  • "This month\'s top 3 tips"
  • "The weekly recap: everything you need to know"
  • "Our new post: a practical guide to [topic]"

Announcement / reminder

  • "Meet our new feature"
  • "Don\'t forget your appointment: tomorrow at 2:00 PM"
  • "[Name], a quick reminder for you"

Test to find the best subject

Instead of guessing which subject gets opened more, measuring is the most reliable way. You can try two different subjects on a small group and send the winner to the whole list. Ulakhane offers this subject line testing feature on eligible plans. For other ways to raise your open rate, see the how to increase email open rate article.

Conclusion: The subject line is your email\'s storefront. A short, honest, and intriguing subject, combined with the right sender name and continuous testing, noticeably raises your open rate.

Frequently asked questions

What makes a good email subject line?
A good subject line is short, clear, and curiosity-sparking; it honestly reflects the email's content. Subjects that stay within about 5-8 words and carry a single clear idea usually perform better.
What should I avoid in a subject line?
Avoid writing everything in capitals, exaggerated promises, many exclamation marks, and spam-triggering phrases like "FREE" or "HURRY". These both reduce trust and increase the risk of the email landing in spam.
How do I test a subject line?
You can try two different subjects on a small group and send the more-opened one to the whole list. Ulakhane offers this subject line testing feature on eligible plans.

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