Subject Lines


What is a subject line?

What to put in an email subject line?

How many characters in an email subject line?

How to write a good subject line?

Should email subject lines be capitalized?

What is an example of a subject line?

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What is a subject line?

The subject of an email is a statement shown in the inbox to represent the contents of the email. Subject lines are important tools for encouraging recipients to open the message.

What to put in an email subject line?

What you put in the email subject line depends on the content of the email. Here are some guidelines based on the type of email:

  • Sales email: customers want to know about the offer. Share that information in the subject line.
  • Newsletter: inform/tease your subscribers of of the content in the email
  • Welcome email: since this is the first email a subscriber is receiving, you should say some form of “welcome” or “thanks for subscribing”

Related: Get Higher Open Rates with 22 of the Best Email Subject Lines

How many characters in an email subject line?

There is no defined number of characters in a subject line. However, depending on the recipient’s device (mobile, desktop, or tablet) and email provider platform, the characters will get cut off at a certain point. It is recommended to keep your subject line under 45 characters to ensure your subject line is fully visible.

How to write a good subject line?

To write a good subject line you should keep the following tips in mind:

  • Keep the subject line under 45 characters
  • Avoid spammy words
  • Personalize the email
  • Don’t use all capitalizations
  • Use action-oriented words
  • Be direct

Related: Your Guide to Writing the World’s Best Email Subject Lines

Should email subject lines be capitalized?

It’s okay to capitalize some of the characters in an email subject line, if it’s not overused. For example: you can capitalize the first letter of each word or capitalize one word.

But you should not capitalize the entire subject line. These type of subject lines are viewed as being too spammy. In these cases the subscriber may delete the email or worse, mark it as spam.

Related: The 6 Most Common Subject Line Mistakes to Avoid

What is an example of a subject line?

An example of a subject line is “Check out these 75 open-worthy subject line ideas”. This is a good example because it’s personalized based on content you want read, it has a strong adjective, and it’s clear what the content will be about.

Related: 75 Open-Worthy Subject Line Ideas

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