It’s likely you already know the popularity and value of email marketing. There are certain aspects of using email that are vital to its success to be opened, like writing effective email copy and building an email address list. But have you ever considered the importance of your email subject lines?

Did you know that the optinmonster website reports that 47% of email recipients open an email based on the subject line alone? At the same time, 69% of email recipients report email as spam based solely on the subject line. In other words, your subject lines have the power to make or break your email marketing campaigns.

Selling the Open Through Psychology

Writing email subject lines that get opened and not deleted or marked as spam is both art and science. We like to call it “selling the open.” Before you can sell anything through email, you have to sell the open. You have to convince users to open the email. The most effective way to do this is by leveraging natural human tendencies and psychological principles.

Some of these are:

Fear – Use a subject line that creates fear of missing out on a great opportunity by adding an element of scarcity (limited availability) or urgency (limited time). Subject lines that include words that imply time sensitivity–like “urgent”, “breaking”, “important” or “alert”–are proven to increase email open rates.

Curiosity – People have a natural desire for closure– we don’t like having gaps in our knowledge. You can leverage this desire by leaving your subject line open-ended so subscribers will be curious, like a cliffhanger that can only be satisfied by opening the email. You can make subscribers curious by asking a question, promising something interesting, or simply saying something that sounds strange or unusual.

Pain Point / Need – If you really understand your buyer persona, you should know their biggest pain points. Use those pain points to get subscribers to open your emails by solving that problem for them.

Humor – If your subject line makes your subscribers laugh, then they’ll simply have to open it. After all, have you ever read a subject line that tickled your funny bone and you didn’t read it?

Being humorous requires a bit more thought and creativity, but it can really pay off in terms of your open rates.

Greed – Everyone wants a good deal. That’s why sales, discounts, and special offers work really well in email subject lines. However, be careful about offering discounts– the higher the percentage discount, the less believable the offer. Nevertheless, you can usually expect to see an increase in your click rates whenever you offer a discount in your subject line. 

Vanity – Everyone has a bit of vanity. People love to be liked, accepted, and even revered by others. That’s why some of the cleverest subject lines use vanity to get you to open the email. To do this, you can either promise something that makes the subscriber look better to their peers, or invoke the fear of being shamed.

Selling the Open with Data

Another way to sell the open for your email subject lines is to use what has already been proven to work, and is still working. Large email marketing companies have all researched everything to do with email, and can provide loads of data on what works and what does not. Use this data and include what triggers email opens in your company marketing emails.

Some Words Boost Open Rates

Some words evoke emotion, interest, or in some other way cause users to open emails. Include these words when relevant in your email titles. Here are some sample words:

  • Fastest
  • Expired
  • Select
  • Daily
  • You
  • Limited

Go here for a larger list.

Some Words Trigger Spam Filters

Just as some words cause users to open emails, other words cause your emails to never make it into the inbox. Here is a sampling of words that trigger spam filters:

  • Budget
  • Cancel
  • Celebrity
  • Download
  • Legal
  • Success

Go here for a larger list.

Numbers & Lists Boost Open Rates

Many of the factors that make up a good blog post title also make a good email subject line. Incorporating numbers into your subject line attracts attention, as our brains are naturally drawn to digits because they are visually compelling.

  • 7 Most Annoying Problems with Email
  • Top 10 Reasons to Avoid Your Boss
  • 6 Survivors Who Should Have Died

Emojis Trigger Higher Open Rates

Companies that use emojis have seen a 56% increase in unique open rates. They seem to add a bit of flare and noticeable color in the inbox. Most email marketers suggest using 1-4 emojis in your subject line will boost your email open rates.

Optimize Your Email Subject Lines for Mobile Viewing

Litmus reported that 50% of all emails are opened on mobile devices. iPhones show about 35-38 characters in portrait mode, and Galaxy phones show roughly 33 characters in portrait mode. Make sure your subscribers who open email on their mobile device can actually read your entire subject line. Most email marketers suggest subject lines that are 17-24 characters, or 3-5 words, long to boost your email open rates.

What kind of advice do you have from your own use of different email subject lines? Share your insights with our readers in the comments below!

About the Author: Donna Amos


I believe you can achieve anything you truly want to achieve. “It might sound trite, but time and time again, I’ve seen it happen with my clients. They overcome the fear of exposing themselves to the possibility of failure to creating profitable exciting businesses. My clients do great work, and sometimes it only takes someone else believing in them to give them the confidence to step out and take the chance.”

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