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How to Write Email Subject Lines That Increase Open Rates

DBS Interactive

A good first impression is important. Whether you’re interviewing for a job, going on a first date, or meeting your significant other’s parents for the first time, the initial impression you make on someone can impact how they view you, choose to interact with you, and ultimately whether they like you.

The same is true when it comes to subject lines in emails.

33% of email recipients open emails solely based on the subject line. 

Source: Convince&Convert

Just like a first impression, subject lines are your initial opportunity to entice readers to open your emails, read your content, and ultimately land on your website and perform a desired action. If readers don’t like your subject lines, they’ll likely ignore or delete your emails.

To help you avoid being ignored or deleted, here are some tips on how to write subject lines that get your emails opened.

Several Types of Effective Email Subject Lines

When writing email subject lines, there are several different approaches you can take. The goal is always to grab your reader’s attention, convincing them that opening your email is key to learning more. With that in mind, it’s important to think about the content within your email holistically, being sure to consider the most valuable actions your readers can and should take once they read your email.


When used properly, urgency and scarcity in your subject lines can be very effective. Urgent and/or scarce messaging makes the recipient feel compelled to take action now, before it’s too late. Doing this too often, however, can come across as disingenuous or even annoying, so you should only consider this tactic when you actually have a time sensitive message to send out, such as a limited-time offer or sale.

Urgent/Scarce Subject Line Example: The Countdown Has Begun!! 24 Hrs Of Discounted Shoes Starts Now
Email Types: Sales, signups, PDF downloads, event promotion


People have a tendency to seek answers for the unknown. If your subject line is mysterious enough, readers will likely be intrigued and open your message to satisfy their curiosity. Engaging that curiosity often means being somewhat vague and puzzling to entice recipients into wanting more.

Curiosity Subject Line Example: Never Tie Your Shoes Again
Email Types: Product announcements, blog posts, news


From a consumer standpoint, it always feels good when you’re being talked to, rather than being talked at. Using someone’s first name, birthday, location, or even a recent order helps personalize your message, and makes the recipient feel like you’re specifically talking to them, rather than feeling like they’re part of a generic mass email to everyone. Add merge tags to your email that help you do this.

Personalization Subject Line Example: Happy Birthday, Dale! Enjoy 25% Off Storewide On Us
Email Types: Exclusive sales/discounts, event promotion, signups, and PDF downloads


People love a good joke. Humor is an incredibly effective way to get people to engage with your brand. Having a funny subject line can make you appear more relatable and human. Be sure to keep it clean and not use offensive humor, otherwise you risk unsubscribes and potential PR issues.

Humor Subject Line Example: Treat Yo Feet
Email Types: Sales, product announcements, blog posts, and news

Frustration Identification

The more you understand about your audience, the better. While it’s important to understand your audience’s likes and needs, it’s equally important to understand their dislikes and frustrations. Starting with a commonly heard frustration is one of the best ways to find new consumer needs that your emails can address. Pointing out a widespread frustration to your audience in a subject line may influence them to open the email to learn what the solution is.

Frustration Identification Subject Line Example: Say Goodbye To Blisters Forever
Email Types: Sales, blog posts and PDF downloads


Stories are a great way to grab someone’s attention. You obviously can’t tell a full story in an email subject line, but you can tell enough of one to interest the reader, and encourage them to participate in the story’s ending: their engagement with your brand. Give your subject line a strong opening that introduces the story in a way that makes reading further irresistible.

Storytelling Subject Line Example: We Gave Away 100,000 Pairs Of Shoes In A Day
Email Types: Sales, product announcements, blog posts, news


Sometimes, the most effective way to get your message across is to be short, sweet, and to the point. Many people appreciate honesty and like the fact of knowing what they’re getting into before opening an email. While some might view this technique as boring, it can be an effective tactic, especially when it’s promoting something you think your consumers will be especially interested in.

Straightforward Subject Line Example: Our Back To School Shoe Collection Has Arrived
Email Types: News, sales, product promotion, blog posts, and PDF downloads

Email Subject Line Tips

Of course, writing an effective email subject line can be a challenge. How do you know what exactly to say, how long your message should be, and what approach to take to get opens? We’ve put together a few tips to help answer some of these questions:

Use Simple Language

Audiences engage with content that makes sense to them, that is familiar to them. If you’re using big, complex words in your email subject lines, you risk losing your reader’s attention. It can also reflect negatively on your brand by giving the appearance you’re using big words just to seem smarter.

Every time you write an email subject line, consider reading it from the reader’s perspective. Think “What part of this news, post, deal or promotion would most appeal to me as a consumer?” Whatever your answer is, that should provide you an immediate idea for what sort of subject line you should use.

If it’s an insanely good deal, I would want that information as quickly as possible, so a straightforward approach might be best. However, if a consumer would find the linked blog post witty and informative, a sassy humorous line may be your best hook. This kind of consumer empathy can shed lots of insight on the direction your subject lines should take.

More Effective Preheader Copy

An example of an email subject line that correlates to the email header.

Just like subject lines are crucial to email opens, so too is preheader copy. Preheader copy is typically the first sentence in the body of your email, often displayed within your email preview located past the subject line.

Some email marketing tools allow you to set preheader copy that is distinct from your email body text, which presents a unique opportunity for you to complement your subject lines with preheader copy that doesn’t have to match the first sentence of your email.

By using preheader copy to build on your subject lines, you give yourself more characters to get your message across and engage more readers.

A/B Testing

There’s no better way to determine the effectiveness of your email subject lines than by conducting A/B testing. The idea of A/B testing is certainly not new, but it’s definitely underused by a lot of companies in their email marketing efforts.

A/B testing consists of creating two identical versions of something, changing a single variable in one of the versions, and testing the two versions against each other by serving version A to half of your audience, and version B to the other half of your audience.

For this example, your email subject line would be the only differing variable between A and B audiences, while the body copy of the email would be exactly the same. When writing your A and B subject lines, think about differing the length, word selection, tone, and various approaches you can take.

Ultimately, the goal would be to verify which email subject lines perform better for your campaigns, in terms of open rates. Once you have some data behind the results, you can adjust the way you write subject lines accordingly, and continually perform A/B tests to ensure your subject lines are as effective as possible.

Think About Mobile

As you probably know, the popularity of mobile has been increasing every year. Whether we’re talking e-commerce, surfing the web, or using social media, mobile devices provide a convenient, on-the-go alternative to desktops. Not surprisingly, mobile devices are also being used more than ever to read emails, and that bears consideration as you write your email subject lines.

Mobile email will account for 22%-77% of email opens, depending on your target audience, product, and email type.

Source: The Ultimate Mobile Email Stats 2018

With such growing popularity, it’s more important now than ever to optimize your emails for mobile, which of course includes your subject lines. Many mobile email tools only display approximately 25-30 characters of email subject lines, so shortening your message is key for engaging those mobile audiences.

Seek Help From Experts

Email marketing is a crucial element of your digital marketing mix. For many companies, email is a massive revenue driver, and the marketing channel with the highest return on investment. To truly get the most out of the emails you’re sending, consider working with a team of professionals that has proven experience in email marketing with a wide variety of clients operating in numerous industries.

If you’re interested in learning more about ways to improve your email marketing efforts, contact the DBS Interactive team.