What Are Email Subject Lines?

11 Subject Line Best Practices

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Email Subject Lines

The "Subject" of an email message should be a short summary of its contents. Email clients usually display it in a mailbox display together with the sender.

The best email subject lines are usually short, descriptive, and provide the recipient with a reason to open your email.

11 Subject Line Best Practices

Experts say that the composition of the subject line is the major determinant of whether the email gets opened.

 Here are some best practices.

  1. Short and sweet seems to work best. The subject line should be no more than 50 characters, as that is the most that can be displayed in the recipient's inbox. According to Return Path subject lines with 49 or fewer characters had open rates 12.5 percent higher than those with 50 or more characters. 
  2. If your subject line is overly "sales-y" it's likely to be marked as spam. Avoid all caps and multiple exclamation points, as well as overtly promotional language like “Buy now” or “Free”.  
  3. Ask a question. Questions pique curiosity and inspire readers to open your email in search of an answer.
  4. Tell then when your offer expires or when you need an answer. Sometimes a deadline makes your email a priority.  
  5. Give the reader a meaningful preview of the value of the email content. Spark their interest by teasing them with the value they are about to receive. Give them one shoe, then drop the other in body copy.
  1. Try a direct call to action. A declarative sentence like "do this now" followed by what they'll get if they do.
  2. Use a number, promise a list. For example, 10 ways to get to work on time, or 3 reasons to drink coffee. People love lists because they take big subjects and break them down into bite-sized parts. A list in your subject line lets your readers know your content is well organized and easily digestible.
  1. Do you have something new and exciting to tell? Is there a development that's relevant to the reader? Let them know in the subject line. Impart enthusiasm. Sharing an announcement will make your email subscribers feel like they’re the first to know and will motivate them to read on for all the details.
  2. Put your business’s name in the subject line. Most people look at who the sender is and the subject line when deciding whether to open the email. Don’t miss the chance to reinforce your specific brand.
  3. Make it funny, punny or amusing. If you do you’re going to get a lot of attention.  
  4. Share something unexpected. This could be anything from a little-known fact about your industry, an eyebrow-raising statistic or just something people aren’t used to hearing.