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Want to Increase Your Email Open Rates? Write Catchy Email Subject Lines

Chad Brooks
Chad Brooks

Learn the do's and don'ts of writing email marketing subject lines.

  • Subject lines are one of the most critical aspects of success for email marketing campaigns.
  • Bad subject lines can have a long-lasting negative impact on your brand.
  • Avoid clickbait subject lines. Certain types of clickbait phrases can reduce read rates by nearly 9%.
  • The best subject lines are personalized and short.

If you aren't getting the results you hope for from your email marketing campaigns, your subject lines could be to blame.

Subject lines are one of the more critical factors in an email marketing campaign's success. Without a catchy email subject line, the likelihood of someone taking the time to open and read the message drops considerably.

Leah Miranda, senior email marketing manager for Campaign Monitor, said good subject lines are vital if you want your email campaigns to succeed. She says the subject line sets the foundation for your subscribers' experience with the email.

"If it's well written, attention-grabbing, and fulfills a need, then the individual will likely open the email and interact with the content inside," Miranda said. "If the subject line is the opposite of that, then there's a good chance it will end up being unread or in the trash."

Dave Charest, director of content marketing for Constant Contact, said other than who the email is from, subject lines are the most important factor in the message being read.

"If an email recipient doesn’t recognize the sender, the subject line needs to work extra hard to entice that person to open it," Charest said. "But if an email recipient recognizes the sender and has a good relationship with the person or business, then that person is more likely to open the email regardless of the subject line."

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Email inboxes are filled with dozens, if not hundreds, of promotional email messages on a daily basis. This is why Len Shneyder, vice president of industry relations for Twilio SendGrid, said he can't stress enough their importance in grabbing the email recipient's attention. A good subject line can start the type of chain reaction businesses are hoping for when they launch marketing campaigns.

"Subject lines are part of a chain of micro-decisions that lead to opening the email, clicking a link in the message body, and hopefully converting the user to the brand," Shneyder said.

The negative effects of bad subject lines

As many agree, the importance of a catchy subject line can't be understated. A good subject line can result in an engaged and long-term customer, while a bad one can lose you a customer forever.

Miranda said the subject line will make or break your email open rates. "But beyond this, it will also affect your click-through, click-to-open rate and even your unsubscribe rate. While subject lines may seem like only one small piece of the entire email marketing strategy, they hold a substantial amount of responsibility in terms of success."

It is important to remember that the more emails you send, the more your name and brand will become tied to your subject lines, according to Shneyder. As a result, notoriously bad subject lines have a lasting negative impact on you and your brand. They can also breed disengagement.

"For example, if I know that a company's subject lines are misleading or overhyped, I might delete the email before reading what it's about," Shneyder said. "Getting your reader to click – to engage – is vital. Breed engagement with good subject lines, and you will keep your spot in the inbox."

Bad subject lines can also draw the ire of mailbox service providers, including Gmail. Shneyder said Gmail analyzes which unopened emails a user deletes. In a move to streamline your inbox, it could send future emails from that company straight into the spam folder. Then, when there is an important announcement, the chances of engagement are almost zero. You will never have effective email campaigns if your messages are getting caught in spam filters.

Why you should avoid clickbait subject lines

Research shows that clickbait subject lines that try to shock you into reading a message and those that promote prices and discounts are among the least effective.

Previous research from the email deliverability firm Return Path found that, while clickbait subject lines like "you won’t believe this shocking secret" are very successful at garnering web traffic, they don't provide the same results over email. Specifically, the use of the phrase "secret of" in a subject line results in an 8.69% decrease in read rates compared with messages containing similar content with different subject lines. Additionally, the use of the word "shocking" had a 1.22% decrease in read rates.

"Marketers should always avoid clickbait subject lines, because if subscribers are over- or under-promised about what will be inside the email, they are likely to unsubscribe or, worse, report the email as spam," Miranda said.

The research also revealed that value-based subject lines highlighting prices and discounts don't perform as well as you might expect. Subject lines containing the keywords "discount," "save," "sales," "clearance" and "free," as well as those with dollar signs and percentages, yielded lower read rates than comparable messages with alternative subject lines. 

While you might get some initial traction with a clickbait subject line, it likely won't result in the type of long-term engagement businesses today are trying to foster with email marketing campaigns.

"You should avoid clickbait subject lines because they only work once, maybe twice," Charest said. "Then you lose the trust of your email subscribers, which is so important to maintain long-term."

The research, which was based on the analysis of more than 9 million subject lines received by more than 2 million subscribers, revealed that a better option is to use subject lines that are benefit-based or have a sense of urgency. The study discovered that those featuring superlatives like "fastest" generate 5.3% higher read rates than similar messages with different subject lines.

Urgency-based subject lines that use words like "limited time," "last chance" and "expiring" also had increased opened rates.

Shneyder said email marketers should consider the perspective of their audience before using a clickbait subject line. What is your reaction to clickbait subject lines? Would you trust the sender of such an email?

"As the sender, you want the receiver to find comfort in your brand popping up in their inbox," Shneyder said. "Be honest with your receiving party, and they will be more willing to listen, to open and – hopefully – to engage."

Writing better subject lines

With so much on the line, it is critical to put some serious thought into your subject lines. There are many do's and don'ts to consider, so these should be far from an afterthought. Here are several tips for writing subject lines that will hopefully entice recipients to not only open your email when it reaches their inbox, but also to click through and become long-term engaged customers.


Personalizing your subject lines is a great start in boosting your open rates.

"By doing something as simple as adding the subscriber's first name in the subject line, it makes the individual feel as though the email was specifically made for them," Miranda said. "When you're looking to advance beyond the first name, you can personalize it based on your subscriber's interests in a certain product, topic or service."

Research from DMR shows that email open rates increase by 17% when the subject line is personalized, while click-through rates rise by 29.6%.


The number of words in your subject line can impact whether someone decides to open it or not. Charest said having short subject lines of 4-7 words is important.

Mobile devices have made this especially important. While the average desktop client shows about 65 characters in a subject line, according to Miranda, mobile phones only display 30-50 characters. Keeping it short prevents your subject line from being cut off when being read on a smartphone.

Important words first

You don't have a lot of time to grab the attention of someone scrolling through their inbox deciding which emails to open. With that in mind, Miranda encourages putting the most important information first to grab their attention.

"For example, if the subject line is 'Summer clothes are 50% off,' your subscriber doesn't find out about the deal until the end," she said. "If you simply swap the order, then the first thing they’ll see is '50% off,' and who doesn't love a good deal?"


To write effective subject lines, you can't just focus on the words. Charest recommends avoiding excess punctuation and symbols in subject lines. He also suggests you steer clear of writing them in all caps.

A/B testing

Instead of guessing what makes for great subject lines, you are better off trying multiple options with A/B testing tools. This allows you to see which subject lines garner more interest.

"Subject lines are one of the easier emailing differentiators to test," Shneyder said. "Always A/B test your email campaigns to measure what's working and what's not."

In addition to the work you put into the subject line, Miranda said you need to think about the preheader text, which is the copy that follows the subject line.

"If you have a great subject line and the preheader text says, 'View message online,' that sounds like a poor user experience," Miranda said.

Image Credit: Suteren/Shutterstock
Chad Brooks
Chad Brooks
Business News Daily Staff
Chad Brooks is a writer and editor with more than 20 years of media of experience. He has been with Business News Daily and for the past decade, having written and edited content focused specifically on small businesses and entrepreneurship. Chad spearheads coverage of small business communication services, including business phone systems, video conferencing services and conference call solutions. His work has appeared on The Huffington Post,,, Live Science, IT Tech News Daily, Tech News Daily, Security News Daily and Laptop Mag. Chad's first book, How to Start a Home-Based App Development Business, was published in 2014.