Writing the perfect subject line is like hunting for gold at the end of the rainbow, at least it can feel that way. It’s likely we agree that most of you don’t believe you’ll actually encounter a leprechaun stirring a cast iron pot of doubloons on the other side of the horizon. I’m also making a leap in assuming you don’t believe you could ever craft an email subject line that will have a 100% open rate. Yet, there’s still part of me attempting to reach that goal – improving my email open rate with an amazing subject line, not wrestling gold away from the character on a box of Lucky Charms.


Most of you know all the elements of a marketing email, especially the subject line. You write them multiple times a day for your personal emails and read them on every email you receive (unless you have the annoying coworker who blatantly ignores the popup alert and sends it anyway).

In marketing emails, the subject line should describe your email’s main offer. Writing that in a way that grabs your reader’s interest isn’t always easy to do. Especially when you begin considering additional elements like character counts (keep it less than 35 characters, so it’s not cutoff on mobile devices), and SPAM filters (don’t say FREE Viagra). But my focus is writing subject lines that lead to better open rates and overall engagement. Doing this correctly is a science. If you’re familiar with our work, you know that we believe interruptive advertising (subject lines) does not have to fail. In fact, it’s the first step in our persuasion equation.  

You’ll notice I said science, that’s because email subject lines are a true science that should include A/B Testing. Yes, testing is scientific research that includes:

Background Research: Know your target audience, where they are in their buying journey and what will motivate them to open your email.
Construct a Hypothesis: Our readers will respond better to subject lines that include the name of a product they’ve already purchased – BTW this was a real test we help execute last fall.
Test Your Hypothesis:  Run your experiment by testing your hypothesis against a control group.
Analyze Data and Draw Conclusions: Look at your numbers, was your hypothesis confirmed or disproved? Why or why not, what can you learn from your data to increase engagement?

Yes, those are science terms, not marketing terms. It’s important to note that marketers (me included) don’t always think like scientists, but we should. Rather than constructing a true test like I described, it’s a common error to simply write multiple subject lines without analyzing or projecting how the audience will respond and simply send them to pick a winner. Yes, you still identify which line will perform better, but you miss out on understanding how, why or what type of writing grabs your audience’s attention.

You’ve seen other people write about using power words or phrases, personalization or other writing tips. These are great ideas, but they still don’t get into testing different categories of subject lines. I know categories is a generic way of stating it, but I’m sure you recognize stuff like “how to” subject lines, question subject lines, or even lines with number play. These categories (yes, I said it again) are a way to develop and test different styles. With that in mind, here are 9 subject line styles you can use.

1. The “How to” Subject Line

A favorite of content marketers, you’ll find “how to” included in email subject lines, blog titles, video titles and more. They’re two words writers love... because when used together, they work.

The “How to” subject line formula works so well because it forces you to describe the content of the email in very clear language. Take these 2 subject lines for example:

  • How to stop smoking in 30 days
  • How to be the best dressed at a summer wedding

It’s pretty straight forward, your audience knows exactly what’s inside when they open emails with “How to” subject lines, which is one of the reasons they work so well. 

The key to success: Focus on the benefit. Sending people instructions on how to learn something seems like homework, say no more. Clearly stating the advantage in your “How to” line articulates value and utility, which are winners for opens, clicks and engagement.  

2. The Question Subject Line

Asking a question in your subject line is a way to focus on your reader’s needs, rather than your brands. Use your audience’s curiosity to spark meaningful engagement by introducing your content as a question that appeals to their interests.

  • Is it okay to wear white after Labor Day?
  • What’s the best wine to pair with seafood?

These subject lines work because the reader can likely relate to these probes and it compels them to open your email and learn more.  

The key to success: Understand the goals or challenges your audience is currently experiencing. Yes, this requires you to know their behavior and where they are in the buying process, but these are steps you should already be taking to enhance personalization within your marketing campaigns. Asking a question that relates to their current situation can increase engagement.   

3. The Command Subject Line

Leading your audience to action using active lines is another effective style. Command headlines direct your audience what to do. They use action verbs and the present voice.

  • Stop baldness before your head looks like a bowling ball
  • Lose weight before swimsuit season

These subject lines work because they share a desired outcome your audience wants to achieve. Using an active voice and action words urges them that the right time is now.

The key to success: Show some risk. Urgency pairs well with command subject lines. Asking your readers to take action “before” it’s too late can be a motivating way to increase open rates. 

4. The Personalized Subject Line

Calling someone by name is one way to get their attention. Working your reader’s name into the subject line of your email adds a personal touch that is likely to catch their eye. Anytime you can make your reader feel like you’re connecting with them on a very personal level, it builds a sense of sincerity. Beyond name, you can add other personal elements based on the details you know about your audience – simple stuff like birthday, anniversaries or items they’ve purchased.

  • Michelle, are you ready for a weekend getaway?
  • Because it’s your birthday!
  • Shoes that will match your new sport coat

By including personalized elements, you create a feeling that you are speaking directly to them and give your email a sense of relevancy that encourages them to open it and consume the content.

The key to success: Personalization is a great experience when it’s done right. It’s also a catastrophe when done wrong. I think we’ve all received emails with bad data merges, you know Dear Fname or some blank spaces followed by a comma (_____,). Have a default setting for anyone in your database who might not match the fields your personalizing. Also, test and test again to make sure you’re not the culprit of bad personalization!

5. The Direct Subject Line

Direct subject lines are just like they sound, direct. They state the value proposition in a straightforward way without any puns, wordplay or hidden meaning.

  • Nike Shoes 25% Off
  • Sale ends at midnight

These subject lines work because there’s no guessing involved. You reader knows exactly what’s in store when they open the email. While these aren’t relevant for all types of communication, direct subject lines standout from hundreds of other emails that clutter your readers inbox.

The key to success: The content (or offer) of your email must exactly match the subject line, otherwise it’s not “direct”. Additionally, segmentation and personalization is a must here as well. Not necessarily the same personal elements of personalized subject lines, but you need to make sure that your direct offer is appropriate for your reader. You would want to send a “50% off summer skirts” email to guys in your database, would you?   

6. The Announcement Subject Line

Also known as “news subject lines,” this style provides your audience with fresh updates. Using words like “introducing” and “new,” your subject line shows the reader that your email contains exclusive information they haven’t heard yet. Beyond products, your announcement headlines can also include awards, accolades or other company greatness.

  • Introducing the all new Silverado from Chevrolet
  • New fashion for the woman who is older than she looks

By using words like ‘Introducing’ and ‘New’ in the subject line, you are letting people know that your email contains new information they don’t know yet and are encouraging them to open the email and learn more.

The key to success: Align your email and content calendar to product development cycles so you’re ahead of the curve in developing announcement emails and using this style of subject lines.

7. The Number Subject Line

Number play is an amazing way to capture your audience’s attention. They not only set a structure for your content (similar to this blog post), but we also live in a Buzzfeed style world where people love lists of 7 best ways to… (insert literally any topic here). To many, numbers are associated with data, and data is associated with facts. In many ways, your readers trust numbers more than other text, so use that to your advantage by including them in your subject lines.  

  • Are you committing the 7 common decorating sins?
  • 5 ways even good lawyers steal from clients

The key to success: Carefully choose the number you use. Your instinct will like be to choose round numbers, figures that end in 0 or 5. However, these capture less interest because they’re associated with an estimate rather than factual data. If you want to win with number play, you need to use real numbers – these numbers are mathematically less likely to end in a 0 or 5 than the eight other alternatives.

8. The Surprise Subject Line

Stating the obvious, but your audience consumes more content now than ever before. I also believe this is an evergreen statement, because I doubt this change anytime in the near future. Knowing that, a pleasant surprise can cut through today’s clutter. Whether it’s a clever pun or an unexpected offer that benefits, using surprise in your subject line triggers an emotional response that increases the chance they’ll open your email campaign.

  • How eating <any topic> makes you a better lover
  • Why <any topic> is better than peanut butter on pancakes

The key to success: Don’t worry about structuring your subject lines in a particular way or use any specific words, but just surprise the reader with something they wouldn’t expect.

9. The Testimonial Subject Line

People act on peer pressure. Without it, we wouldn’t have the double dog dare. While peer pressure has a negative connotation, peer reviews can be a positive. Your audience is influenced by online reviews. In fact, online platforms like Yelp and Trip Advisor are proving that. Testimonial subject lines use real peer reviews to capture your audience’s attention. Fitness brands and weight loss companies do this better than anyone.

  • How I lost 70lbs without exercising

Your audience trusts 3rd party reviews because they know your brand is attempting to influence them. 3rd party content is genuine, honest and can be your best advocate, so use it!

The key to success: Testimonial subject lines must be REAL testimonials from actual reviews. Your audience will sense statements that aren’t authentic, and that can lead to a slippery slope of negative outcomes. Honesty is the key here!

In Conclusion

Your subject line is in many ways the single most important element of your email. Yet, it’s often written as an afterthought with very little strategy in mind. Plain and simple, subject lines must be a priority. It’s what entices your reader to open your email and pursue the information inside, so give it the attention it deserves.