Email Subject Lines: What They Are and 11 Tips for Writing Them

Get your email recipients to open your emails

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The Subject area of an email is a short description of the message. Writing a good email subject means keeping it concise and to the point to summarize what the email is about.

When the recipient receives your email, the subject line typically shows near your name, before the email's body. It's one of the first things someone sees when receiving an email, so it's a first impression of sorts.

Email subject line

An ideal email subject line is short and descriptive; it gives the recipient a reason to open your email. If it's too long, an email client might truncate it. If it's too short or missing, it won't provide the reader with any way to know what the message is about or to skim the inbox quickly in search of your message later.

11 Best Practices for Writing Subject Lines

Beyond avoiding vagueness and verbiage that's unrelated to the message content, below are some best practices to consider when writing email subjects.

  1. Short and sweet usually works best. The subject line should be no more than 50 characters; that's the most that a recipient's inbox can display. 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. Avoid using all caps, exclamation points, and overtly promotional language. If your subject line is overly "sales-y" — e.g., BUY NOW!, One Time Offer, FREE! — it will probably end up in the recipient's spam folder.

  3. Ask a question. Questions pique curiosity and inspire readers to open your email in search of an answer.

  4. Mention a deadline, if applicable. Tell the recipient when your offer expires or when you need an answer. Sometimes, a deadline makes an email a priority.

  5. Give the reader a meaningful preview. Spark interest by teasing with the value of the content. Drop one shoe in the subject line and the other, in body copy.

  6. Use a direct call to action. If you want your email to provoke action, use an imperative sentence such as "Do this now" followed by what the recipient gets in return.

  7. Use a number and promise a list. People love lists like "10 ways to get to work on time" and "3 reasons to drink coffee" because they break big topics into bite-sized parts. A list in your subject line lets your readers know your content is well organized and easily digestible.

  8. Announce your exciting development, event, or idea. Impart enthusiasm. Sharing an announcement makes your email subscribers feel like they’re the first to know and motivates them to read on for the details.

  9. 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 brand.

  10. Make it funny, punny or amusing. Entertaining content is appealing.

  11. Share something unexpected. This might be a little-known fact about your industry, an eyebrow-raising statistic, or just something people aren’t used to hearing.