8 Tips for Writing Effective Email Subject Lines

The job of a subject line is simple: Get the reader to open the email.

On average, 33 percent of recipients open emails based on it's subject line, so it’s incredibly important to get it right — because even the most enticing email in the world won’t matter if the reader ignores it.

There’s plenty of insight and data across the web on best practices for email marketing, but here are five key tips to help you write an attractive subject line that will not only draw in your readers, but your buyers and prospects.

Branded Email

Tip 1: Go Easy on the CAPS

Contrary to what some of history’s most prolific spammers believed, writing a subject line in all caps will not guarantee an open. In fact, IT’S A GREAT WAY TO LOOK SPAMMY.

While one or two fully capitalized words alone won’t get caught by the filters, it does edge you closer to the dreaded spam folder. Capitalization can be a powerful tool to draw attention where desired, but with great power comes great responsibility. Use it sparingly and professionally. Capitalizing as you would a title seems to be an unofficial industry standard.

Uncle Ben Spider Man Gif

Studies have also suggested capitalizing the first letter, like in a sentence, works as well and, sometimes, maybe even a little better than other styles.


  • This is the Most Common Industry Practice
  • This also gets great open rates

Tip 2: Make a List

People like lists. Perhaps it’s the promise of information diced into easily digestible snippets or maybe it feels like zeroing in on the most important aspects of a given topic. Whatever the reason, people on the Internet enjoy consuming information via numbered/bulleted lists!


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    (Did you try to click?)
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Tip 3: Personalize the Message

Personalization in the subject line can be quite a contentious topic. One study from MailerMailer suggests that including names in the subject line may actually be detrimental to open rates. However, the data scientists at MailChimp say that personalizing subject lines to include the recipient’s full name can positively impact open rates.

Aside from names, location is another convenient and beneficial personalization to include in the subject line. The good news is location personalization is universally considered a best practice!

Last but not least, consider tying in current events when relevant to your subject.


  • Bob, are you attending CES in January?
  • Where to find the best BBQ in Austin

Tip 4: Create a Sense of Urgency!

While people don’t like to be yelled at in all CAPS, they do respond well to time sensitive material. The fear of missing out can be a powerful motivator. Key words like “Urgent” or “Breaking” can positively impact open rates. Similarly, creating a deadline for an offer can also improve your click-through rate.


  • Last Chance to Reserve Your Valentine’s Dinner
  • Urgent: Save on crazy socks this weekend only
5 Ways To Increase Your Email Open Rates

Tip 5: Keep it Short

Your recipient doesn’t have a lot of time or patience, so when choosing between a personal correspondence, a cookie recipe from grandma, and your company’s promotional email blast, what do you think he or she will click on?

Keeping your subject line short and to-the-point is instrumental to establishing a good first impression with the recipient. The ideal subject line lays out the point of the email and sets the expectations for when the reader opens it. This should all be accomplished in 50 characters or less. The sweet spot appears to be between 28-39 characters.

Get to the point or risk losing the reader. The Internet has a name for subject lines like this, which are far too long. It’s called TL;DR (Too Long; Didn’t Read).


  • 7 Tips for Writing a Concise Subject Line
  • Insight on writing a great subject line 

Tip 6: Offer Your Readers Something

People love something new and shiny — perhaps even something discounted or free. Did you just put together a new eBook that showcases your subject matter expertise? Good news, your potential buyers probably want to hear about it. Hit them with a downloadable offer right in the subject line to pique their interest of what the email may contain. Put what you have right on the table, and don't beat around the bush. 

Not only will adding an offering to your subject line persuade someone to open your email, but it's more than likely going to drive them to your website for lead generation as well. 


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Tip 7: Using Call-To-Actions In Your Subject Line

Subject lines are similar to CTAs in that the language should inspire someone to click your email and open it. Using action oriented words can help reinforce a sense of urgency and excitement that should come when receiving something new in your inbox. Language that includes a verb is more clickable and engaging than a line that is solely a descriptor descriptor. 


  • Meet your potential customers
  • Engage with in-market buyers

Tip 8: Engage Your Audience With Exclusivity

Are you promoting a trade show you're attending or perhaps hosting a webinar? People love being included in something that's exclusive, even if it is an event open to all. Make your readers feel special because the outcome can be pretty powerful when trying to increase open-rates. 


  • You're invited: Together For Industry
  • An exclusive offer just for you

Bonus: Curious Of Our Best Subject Line?

A great subject line has a high open rate. According to MailChimp, the average open-rate for an email in the manufacturing sector is 20.5 percent. So far in 2019 Thomas has crushed this open-rate with an email we sent out that promoted our Q1 2019 Sourcing Activity eBook. This email saw an open-rate of almost 28 percent, and we have to credit it to a simple yet, successful subject line. "What buyers sourced in Q1 2019." Yes a great tip for subject lines is to provide a sense of urgency, but in this case curiosity produced a result. 

We hope you’ve enjoyed reading about these tips to write a more effective subject line. Follow these best practices and test, test, test. Want more marketing tips? Sign up for the Thomas Industry Update to stay up to date on industry news and trends, and more. 

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