What Makes the Best Email Subject Lines?

What Makes the Best Email Subject Lines?


In email marketing, the subject line is the most powerful element. They are the first impression – and sometimes last – for your readers. They have the power to entice people to click and engage or to simply pass by unnoticed. Crafting the best email subject lines isn’t just a good idea – it’s essential. Make sure your message doesn’t drown in the sea of emails in an inbox; a good subject line is your chance to stand out in the crowd!

Because we understand the importance of having the best email subject lines, we have compiled a list of the best tips and tricks. 


Keep reading to discover what makes the best subject lines and how to craft them yourself. 

1. Understanding the Importance of Email Subject Lines

Subject lines serve as the gateway to successful email marketing campaigns. They influence open rates and overall performance. Subject lines are often a quickly written afterthought, but some would argue that they are even more important than the body of the email. After all, the world’s best email holds no value if it is never opened! 

Studies have consistently shown that well-crafted subject lines can significantly impact open rates. Check out these powerful stats: 

  • Emails with personalized subject lines have a 26% higher open rate than those without (Hubspot) 
  • A simple subject line change resulted in a 93% increase in open rates (MarketingSherpa)
  • After reading the subject line, 69% of email recipients mark emails as spam. (Invesp, 2021)
spam and email subject lines statistic

These statistics underscore the critical role subject lines play in capturing audience attention and driving campaign success. Effective subject lines not only increase open rates but also set the stage for the entire email content. Ultimately leading to higher click-through rates, conversions, and overall campaign effectiveness. 

2. Key Elements of Effective Subject Lines

Now that we have established why your subject line is important, let’s look at what makes them effective. 

Length: A good subject line should be concise and to the point, aiming for around 6 to 9 words or roughly 40 to 60 characters. (Mailchimp)

Think: short and sweet! 


Clarity: Clarity and relevance are supreme when crafting effective email subject lines. It should clearly communicate the content or purpose of the email. The goal is to immediately capture the recipient’s attention and entice them to engage further. 

Here are some good examples of clear subject lines: 

  • “Introducing Apple Watch Series 9 and Apple Watch Ultra 2” Sender: Apple
  • Brighten and hydrate dull skin just in time for spring! Sender: Truly Beauty
example of good email subject line


Personalization: In a world where customers crave genuine connections, being more than just a number is key. Elevate your marketing strategy by embracing personalization. 

By tailoring your emails to resonate with individuals, you build trust and rapport. This can also significantly enhance engagement rates. You can do so by crafting personalized subject lines that speak directly to your audience. 

A couple of examples of personalization in an email subject line are: 

  • “Hey [Recipient’s Name], Exclusive Offer Just for You!”
  • “Happy Birthday from the IKEA Family!” Sender: IKEA


Urgency: Subject lines with urgency are effective because they trigger a basic human fear: the fear of missing out (FOMO).

When people perceive that time or availability is limited, they are more inclined to take immediate action to avoid missing out on an opportunity. 

This sense of urgency creates a feeling of importance and priority, convincing people to open the email and act quickly.

Some good examples of urgent email subject lines include: 

  • LAST CHANCE: Our blockchain webinar is next week!
  • “The timer’s going off on your cart!” Sender: King Arthur Flour
  • FLASH DEAL ⚡️(first 100 people only) Sender: Jesus Loves You 


Curiosity: Curiosity-driven subject lines captivate recipients by teasing intriguing information or promises, sparking their natural inclination to seek answers. 

By hinting at something unknown or surprising, these subject lines create a sense of excitement and curiosity. That then entices recipients to open the email to satisfy their curiosity. 

Like the saying, “Curiosity killed the cat, but satisfaction brought it back.” Leveraging this psychological trigger not only boosts open rates but also encourages deeper engagement with the email content. 

Here are a few great examples: 

  • “A Sneak Peek for VIPs Only.” Sender: Serena & Lily
  • “You’re missing out on the full power of Calendly.” Sender: Calendly
  • “Our #1 most asked question…” Sender: Supergoop


3. Emojis in Subject Lines

Emojis have become a universal part of digital communication, and their presence in email subject lines can be significant. Adding emojis can show personality, emotion, and visual appeal in subject lines. This can make them stand out in crowded inboxes and entice recipients to open emails. 

Studies have shown that emails with emojis in their subject lines often experience higher open rates compared to those without. Check out these interesting findings: 

  • Emojis in subject lines increase the effectiveness of marketing by 70%. (OptinMonster, 2020)
  • Emails with emojis in their subject lines have a 39% open rate on average. (Klaviyo, 2023)

Use emojis thoughtfully for fun and impactful communication. When choosing emojis in a subject line, ask yourself the following questions: 

  1. Does this fit my brand’s tone and voice? 
  2. Will it resonate with my target audience? 
  3. Does it detract from my message? 

We want emojis to be helpful, not harmful. Overusing emojis may decrease engagement or even result in being marked as spam. Research by Mailchimp found that: 

  • Businesses should only use one emoji at a time. (Mailchimp)

Here are examples of strong subject lines with 1 emoji count: 

  • Mark your calendars 📆 Q1 is almost here! Sender: Data Axel 
  • “New recipe alert 🚨” Sender: Hello Fresh
  • “You were on point last week 🎯”Sender: Grammarly


4. A/B Testing Subject Lines

A/B testing is a crucial tool to determine the most effective subject lines that resonate with their audience. By comparing different subject line variations, you can gain valuable insights into what drives higher open rates, click-through rates, and overall engagement. 

What is A/B testing? 

Setting up an A/B test for subject lines involves dividing the audience into two or more groups and sending each group a different version of the subject line. 

Factors to consider in A/B testing include:

  1. The wording 
  2. The length 
  3. Personalization 
  4. Use of emojis or special characters 

Analyzing the results will allow you as the sender to refine your strategies and optimize future email campaigns for maximum impact.

For example, a clothing retailer might conduct an A/B test to compare subject lines promoting a “30% off” discount versus a “limited-time offer” for the same sale event. 

The test could reveal that the “limited-time offer” subject line generates a higher open rate and conversion rate, indicating that the sense of urgency resonates better with the audience. 

A/B testing allows you to make data-driven decisions and improve the effectiveness of email campaigns.


5. Best Practices for Writing Compelling Subject Lines

Writing compelling subject lines requires a strategic blend of actionable language, exclusivity, avoidance of spam triggers, and personalization to captivate recipients. 

Once they are captivated, the goal is that they engage. 

Actionable language prompts an immediate response by conveying a clear call to action, such as Get Instant Access!” or “Sign Up Here!” 

Creating a sense of exclusivity makes subscribers feel valued and privileged, enticing them to open emails for exclusive offers or content tailored specifically to them. 

To avoid spam triggers, it’s important to steer clear of overly promotional or deceptive language and instead focus on sincerity and relevance. 

Adding personalization through the use of recipients’ names or tailored content enhances the connection with subscribers, making subject lines more compelling and increasing the likelihood of engagement.

For example, a subject line like “Exclusive Deal Just for You: Claim Your VIP Discount Now!” combines: 

  1. Actionable language 
  2. Exclusivity 
  3. Personalization 

These 3 “ingredients” create a compelling message that encourages immediate action while making the recipient feel valued and special.



In email marketing, the subject line serves as the gateway to engagement and conversion. While the task of crafting the perfect subject line may seem daunting, it’s a piece of the puzzle that demands attention. 



We hope you feel well-equipped to craft email subject lines that capture attention and drive engagement. As you embark on the subject line journey, remember to tailor your approach to suit your audience’s preferences and needs. To recap, here are some final pointers to keep in mind:

  • Keep subject lines concise, aiming between 6-9 words. 
  • Personalize subject lines to make recipients feel valued and connected.
  • Utilize emojis judiciously to enhance visual appeal without overwhelming the message or feeling spammy. 
  • Conduct A/B testing regularly to refine your techniques and understand what resonates best with your audience.
  • Strike a balance between staying current with trends and maintaining a personalized touch.

Ultimately, craft subject lines that you would find compelling and compelling to open yourself.

As you experiment with different techniques and strategies, remember that crafting the best email subject lines is a journey of continuous learning and refinement. 


Email Marketing Help? 

If you are looking to up your email marketing game, we are here to help! At Lake House Digital, we offer email marketing services and will handle everything from crafting unique subject lines to creating the best newsletter your readers will love. To get the conversation started, send us a quick email to hello@thelakehousedigital.com. We can’t wait to chat with you!

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About Lake House Digital

Lake House Digital is based in Cary, NC near the Research Triangle Park (RTP). We provide measurable, actionable results in digital marketing efforts for our clients. We thrive in staying educated with the most current trends and algorithms in the digital world. And, we do this while staying true to best practices in marketing. In the industry, we are set apart in that our employees hold industry certifications across topics and platforms. Lake House Digital has worked with B2B and B2C clients in life sciences, technology, manufacturing, healthcare, commercial real estate, hospitality, higher education, and nonprofits. We bring experience with a growth mindset to achieve the very best results: measurable, actionable results and growth for every client.  www.thelakehousedigital.com