25 Best Email Subject Lines To Boost Open Rates [Updated]

email subject lines

Do you know how long it takes to nail that first impression?


Yes, you read that right. Not hours, not minutes, but seconds.

That’s why you need an eye-catching email subject line, every time you send an email.

Maybe you’ve written an amazing email body, but if your subject doesn’t cut it, your readers won’t open the email.

According to statistics, emails have the highest return on investment. For every $1 spent on email marketing, there is a return of $32. Over the years, email marketing has been a favorite among marketers because it is easy to plan, implement, and improvise.

In this blog post, we’ve compiled a list of 25 of the best email subject lines on the internet. We’ll also show you how to write catchy subject lines. 

Keep reading to find out more!

👉👉Get FREE lifetime access (up to 15 users) to EngageBay – the simplest and powerful email marketing and marketing automation software for growing companies from here. Signup and setup free email campaigns in minutes. 🏆🏆

What is Open Rate?

Email open rate is the percentage of the total number of subscribers who have opened an email.

These rates depend on various factors, including email subject line, relevancy for subscribers, personalization, content, etc.

However, a value in the 20-40% range can be considered a healthy open rate. Various factors impact open rates, and the subject line is one of them.

subject line best practice

Image Courtesy: http://www.anchorcomputer.com/index.php/2016/04/19/personal-email-marketing/

Email Subject Line – A Defining Parameter

Did you know that 47% of email recipients open email depending on the subject line, whereas 69% of email recipients report email as spam based solely on the subject line?

So, you can see how subject lines directly impact email open rates.

People read or trash emails based on what they see in the subject line.

However, when you add personalization to subject lines, they are 22% more likely to be opened. 

So, the more eye-catching the email subject line is, the more people will be inclined to open the email. 

Now that you know about the importance of that ‘one line’ that has the potential to grab the attention of customers, let us take a look at some of the best email marketing subject lines from the industry in 2021.

holiday subject lines

25 Catchy Email Subject Lines From the Internet

  1. “Google sees smartphone heroics in Oreo. It’s The Daily Crunch.”: TechCrunch is a newsletter that keeps people updated about the latest news and developments from the world of technology.

So, using the words ‘daily crunch’ keeps you abreast with updated information about technology, so you know you gotta read it.

  1. “Where to Drink Beer Right Now” (Sent at 6:45 AM on a Wednesday): It could have been better timed by Eater Boston.

After a busy day midweek, this can be the perfect thing to wake up to and ease out a bit.

  1. “Uh-oh, your prescription is expiring”: Using conversational words like “uh-oh” invokes the fear of missing out. Here, Warby Parker used this line to attract customers to buy glasses. 
  2. “Best of Groupon: The Deals That Make Us Proud (Unlike Our Nephew, Steve)”: A sarcastic or humorous line can pique the interest of readers. And Groupon uses this strategy to the best.
  3. “*Don’t Open This Email*”: When we are told not to do something, we tend to be more curious to open the content and read. This is what Manicube used in their marketing email subject line.
  1. “What They Eat In Prison,” “DO NOT Commit These Instagram Atrocities”: A catchy language always urges the reader to look forward to interesting content.

Thrillist uses eye-catching sentences such as these in their subject line to entice readers. 

  1. “Black Friday shoppers are the worst customers”: This came in a LinkedIn Pulse newsletter, promoting an article one of its users wrote on the topic of holiday marketing.

Giving intriguing facts and figures make the reader want to open the email.

  1. “10 bizarre money habits making Millennials richer”: Subject lines that are leading will always urge the recipient to know more about the subject.

Refinery29 uses such leading subject lines to make the email marketing titles more appealing to their followers. 

Choosing a great subject-line can be a game changer.


  1. “Not Cool, Guys”: BuzzFeed is known for its unique and interesting content.

Sometimes they use a combination of the subject line and preview text to make it conversational and friendly.

For example, the preview text that followed this was “Okay, WHO left the passive-aggressive sticky note on my fridge. Honestly, who acts like this?”

  1. “Is this the hottest career in marketing?”: Digital Marketer used this curiosity-inducing subject line to let readers know what’s interesting inside.
  2. “? Free (Cool!) Clothes Alert ?”: Clover uses visual content like emojis to lure readers into opening the email.
  3. “You free this Thurs at 12 PM PST? [guest blogging class]”: Mary Fernandez used personalization to reach out to new readers and existing followers.

Personalization can work wonders and urge the recipient to open the email as it makes them feel special.

  1. “1,750 points for you. Valentine’s flowers & more for them.”: 

When you read this line, you’ll immediately want to know who the flowers are for. This prompts you to read the body. Cryptically worded subject lines are a fantastic way to entice readers.

  1. “Rock the color of the year”: Etsy, the e-commerce website, was able to promote a product solely based on color. We’ll want to know what ‘the color of the year’ is, right?
  2. Sometimes, straightforward subject lines also work best. For example, “[Company Name] May 2005 News Bulletin!” or “Eye on the [Company Name] Update (Oct 31 – Nov 4)”, etc.
  3. “As You Wish”: UncommonGoods knows its buyer personae and sends emails based on the wish lists or interests of its customers. This subject line is based on the movie ‘The Princess Bride.’
  4. “Everything you wanted to know about email copy but was too afraid to ask”: CopyHackers uses one of your fears or pain points to urge you to take a quick look at the email.
  5. “The price dropped for something in your cart”: These retargeting email subject lines can prompt you to visit your cart once again or complete some unfinished purchases. 
  6. “Tonight Only: Get this NOW before it’s gone…”: It is difficult to resist FOMO, or Fear of Missing Out.

Violet Grey uses this with an added incentive to increase email open rates

  1. “New Video: (Topic)”: An effective email campaign should not only increase sales but also provide value to customers. 
  2. “Yes, this is a fundraising email”: Al Franken
  3. “Hey”: Barack Obama

These straightforward and seemingly “boring” subject lines performed the highest out of 40 million emails, with open rates between 60-80.

  1. “Products the celebs are wearing”: Sephora used this celebrity branding and vanity subject line to hit the emotional quotient of readers and make them open the email.
  2. “Learn a language with only 5 minutes per day”: Offering a solution to a problem or trying to address a pain point is a good strategy when writing an email subject line.

Duolingo gave a great offer while trying to solve a problem.

  1. “We Need To Talk…”: A recent email marketing campaign by PPC Protect saw an impressive open rate of 63% using this simple subject line.

Not only does it make the email look important, it also triggers the reader’s curiosity.

Steps for Writing the Best Subject Lines for Emails

Here’s how you write a fantastic email subject line.

Curiosity: Curiosity is something that works wonders. Add text or content that will invoke interest in the reader’s mind.

Urgency: Using urgency is a classic approach and generally works because it compels the reader to take immediate action. 

Relevance: Subscribers want timely and trendy information, and that’s what you should be giving. This idea should be leveraged while designing subject lines as well. Trendy topics or trendy headlines should be used in subject lines to keep readers interested.

Personalization: Personalization offers a feeling of importance and is one of the best strategies in content marketing. It not only helps retain good relationships but also generates more leads. Here are some examples:

email subject line character limit

email subject

Celebrity Branding: Use a familiar name so people can identify it right away. Personality traits of celebrities can invoke curiosity in the recipient to open the email.

Email Subject Line Best Practices

1. Keep it short and simple. Be precise

Almost 77% of emails are read on the phone, so if the subject line is too long, it might get cropped. The reader might overlook important information or might be disinterested.

So, you should keep your subject lines within 50 characters so that your followers can read the entire subject. Think about the words which matter the most and exclude unnecessary details.

For example, instead of writing ‘Order No #XXXX is being processed,’ you can simply write ‘Your order is being processed.’

Also, be precise with your subject lines.

For example, use ‘Increase your sales by 60%’ rather than ‘How to increase your sales.’

2. Avoid ‘no-reply’ sender name

A person’s name, like Roger@yourcompany.com, will be more acceptable to an individual than a company name. A familiar name ID gives a feeling that they are dealing with an actual person rather than an abstract entity.

It is also important never to send emails with a no-reply sender name as they directly go to spam and are usually ignored.

3. Avoid using ALL CAPS

Study shows that 85% of recipients prefer subject lines in lower case. Fully capitalized subject lines look spammy and will be ignored by readers. 


Don’t you get the feeling that someone’s screaming at you?

Instead, use simple and delightful language to get your reader’s attention.

4. Segment your lists

It is always better to send emails relevant to your recipients.

That’s why personalization is the way to increase open rates. List Segmentation is a major aspect of email marketing and will help you send the right content to the right person.

You can read about how CRM software can aid in automatic list segmentation here.

5. Avoid making false promises

Do not make false promises in the subject line and deviate from them in the email body content. This is called clickbait and is usually frowned upon. 

Though your subscribers will initially click on these links, they’ll soon lose faith in you. 

6. Use numbers and values

A subject line containing numbers will get more attention than vague ones.

Try to add numbers and values wherever possible to attract readers. You can mention the discount value or use numbers to refer to the size of your listicle.

7. Make the recipient feel special

The power of personalization cannot be understated. People want to feel valued. 

Choose sentences that instantly grab the attention of the recipient and make them feel special. Here are some great examples:

  • “You’re invited!”
  • “For our beloved customers only”
  • “An exclusive offer for you”

8. Give an engaging pretext

A pretext is not part of the subject line but appears right next to the subject line in the inbox.

It is partly visible to the recipient and has an impact on readability. The preview text shows a bit more on what’s inside. So, to keep it precise and engaging, set the pretext to suit your recipient.

9. User personalization token

Research has shown that marketing emails that included the recipient’s first name in their subject line had higher clickthrough rates.

Including first names in the subject line can be a great start. A dog walking company, Wag!, uses this technique to its advantage by adding the owner’s dog’s name in the subject line.

10. Use Questions to Seek Attention

Asking a question in the subject line can be an attention-seeking strategy.

 “Are you making these SEO mistakes?”

“Do you know what went wrong with your website?”

These subject lines can be hard to resist as they usually resonate with your audience. 

11. Start with action-oriented verbs

Call-to-Action subject lines can prompt readers to take action. For example, while inviting people to a hockey legend dinner, the email subject line can be, “Dine with Bruins legend Bobby Orr.”

12. A/B test your subject lines

Though the tips and tricks mentioned above do wonders, it is always better to A/B test your subject lines to know what works best for your audience.

Email A/B testing will help you understand what prompts people to click on your emails so that you can improvise according to the results.

Reduce Bounce Rates with Email A/B Testing.



We hope this blog post helps in improving your understanding of email subject lines. 

As a marketer, it is important to grasp the true performance of  your email marketing campaigns

Quantifying your open rates and campaign successes can’t be done manually. 

There are dozens of tools to help you analyze your open and clickthrough rates, segment your audiences, and A/B test your subject lines. 

One such software is EngageBay. It’s much more than just an analytics tool, though. 

EngageBay offers an all-in-one marketing, sales, and customer service platform with integrated CRM. You get powerful tools, including omnichannel marketing, customizable emails with drag-and-drop email builder, intelligent segmentation of contacts, predictive lead scoring, A/B testing of all email and landing page elements, powerful and customizable reports, and so much more. 

If you’d rather watch a video first, we’ve got you covered. Check out this comprehensive demo from our developers:

👉👉Get FREE lifetime access (up to 15 users) to EngageBay – the simplest and powerful email marketing and marketing automation software for growing companies from here. Signup and setup free email campaigns in minutes. 🏆🏆

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Debolina Coomar is a creative writer and blogger. She writes for EngageBay about email automation and other best practices in modern marketing.

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