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100 Cold Email Subject Lines To Guarantee a Response

By Dmitry Dragilev 6 Comments Last updated on October 12, 2017

I think you’ll agree with me when I say:

The challenge all marketers face today is making sure their emails are actually read.

Emails are an integral part of modern day life, with over 206 billion emails sent every single day.

With the sheer amount of emails flying around, it is near impossible to predict whether your email will be opened or trashed.

But here’s the kicker…

Write a powerful email subject line and you have won the battle.

These little fellas can make all the difference between creating a new viable lead or your address ending up on a block list.

As such, it’s more vital than ever to make sure you’re nailing them every time.

To help, I’ve teamed up with Lucy Literado of Reply.io to analyze 100 examples across a wide variety of different industries.

In this post, you’ll:

  • See examples of the email subject line best practices for inbound, outbound and customer emails
  • Learn the essential principles to create your own eye catching cold email subject lines

How to craft cold email subject lines that stand out

Before we get to the examples, take a moment to familiarize yourself with these tips for creating powerful subject lines:

Keep it short and sweet

It can be tempting to cram as much information as possible into your subject line, making sure you spell out every single point that’s in the email.

However, concise subjects are more likely to hook readers. Remember, most email clients will cut off the subject line after a small number of characters, so make each word count. There’s no room for fluff here!

 

Personalize, Personalize, Personalize

One of the biggest challenges in any kind of email campaign is making the email personal to the recipient.

At the most basic level, you can use the recipient’s name.

At a deeper level, make sure the subject appeals directly to that customer, to their interests, to the challenges they face. By carefully segmenting your list, you can then tailor the subject line and email to very specific groups.

 

Give them a reason to click

Any successful subject line works by giving the reader a reason to open the email, to learn more.

There are two key ways to do this: The first is by clearly outlining what the email contains; whether it’s a special offer, a case study, or something else. The other is by creating curiosity, where you ask a question or make a statement that is designed to grab the reader’s attention.

 

Highlight urgency

Sometimes an email will sit in my inbox for months without being opened. The subject line looks interesting, and I’m sure it’ll be worth reading.

But with a million and one things already on my to-do-list, it’s easy to save emails for tomorrow.

If you can legitimately give your recipients a reason to open your email immediately, you raise the chances that it’ll be read. For example, if the offer ends tomorrow, or if there are only 5 seats left for your conference, then highlight this in your subject line.

 

Use testing to optimize results

The truth is you can create good subject lines by using these principles, but creating great subject lines requires testing.

Simple A/B split testing will help improve your subject lines and ensure that they are working for your specific audience.

Remember that for effective A/B testing, only change and test one piece of the subject line at a time, otherwise you can’t be sure what worked and what didn’t.

 

Now that we’ve covered some of the key principles, let’s crack on with the 100 examples. As you read them, take the time to see how they utilize these principles, so you can do the same with your own subject lines.

NOTE: This entire post is worth reading from beginning to end. However, you can also jump to specific categories:

Curiosity

Curiosity based subject lines primarily target our emotional need to close an open loop. You can’t help but  check out what the email is about. You will notice that these emails hardly appeal to our logical brain. The subject will tell you practically nothing about the content of the email and how it will be useful for you, and yet you will feel compelled to open it on a busy day!

However, make sure that the body of the email lives up to the promise! Nothing is worse than opening an email which is not even half as interesting as the subject. Avoid clickbait and use this judicously.

Here are a few great examples:

Subject line: Are You Prepared for This?

  • Sender: JivoChat
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

This subject raises curiosity levels straight through the roof, while also incorporating fear based motivation. If you need to be prepared for something, that means something’s changing. This sparks reader’s interest and ignites fear of being unprepared for an important event.

2. Subject line: How would you answer this question?

  • Sender: WorkRails
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

This is a clear example of creating an open loop and raising curiosity in the reader’s mind. To find out what the question is, you’ll have to open the email. More than that, the subject asks the recipient to formulate an answer to this unknown question, demanding more of their focus and attention.

3. Subject line: Looking to Learn More?

  • Sender: WriterAccess
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

This subject line is similar to the example above.

4. Subject line: It’s not big. But it is clever

  • Sender: Radir Ltd
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

A clever play on a well-known phrase helps this email stand-out in the inbox, arousing curiosity. It can be risky in outbound where the recipient isn’t aware of your company, but the cold email subject line does enough to make you stop and look twice.

5. Subject line: Why we don’t want to fill your vacancies

    • Sender: Sigma Recruitment
    • Type: Outbound
Dmitry
Dmitry and Lucy's take

A clever play on a well-known phrase helps this email stand-out in the inbox, arousing curiosity. It can be risky in outbound where the recipient isn’t aware of your company, but the cold email subject line does enough to make you stop and look twice. This email works by going in the opposite direction of the reader’s expectations. Why wouldn’t a recruitment company want to fill your vacancies? The apparent logical inconsistency grabs attention and encourages recipients to open the email and find the answer.

 

6. Subject line: *Don’t Open This Email*

  • Sender: Manicube
  • Type: Online example
Dmitry
Dmitry and Lucy's take

You can’t help but love the reverse psychology here. It speaks to our innate curiosity, and our overwhelming desire to do what we’re told not to. How many times have you checked a ‘Don’t touch, wet paint’ sign? It’s practically wired into our DNA.
However, this is another one I’d use sparingly.Used once it’s a charm. The second time it’s a cheap gimmick. And if the contents aren’t worthwhile or explain why the reader ‘shouldn’t’ have opened the email, then they’ll feel tricked. Remember, nobody likes to be tricked.

7. Subject line: utm_medium=email&utm_campaign=jun2017&utm_source=just-landed

  • Sender: Auto Pilot
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Auto Pilot knock the curiosity factor out the park on this one. While it may look like a mistake at first, the email quickly explains that the ‘jumbled string of text and symbols is what UTM parameters look like, and they’re super important for tracking marketing ROI.’ It’s a risky move, and I wouldn’t try this on a cold email, but as an email to an opt-in list of tech-savvy marketers, it certainly stands out.
What could stand out in a similar way in your industry?

8. Subject line: Bad SEO Advice

  • Sender: Backlinko
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

I love subject lines that switch things up and start from a negative. When good advice is a dime a dozen, ‘bad’ advice stands out and kicks the curiosity factor up. I refer to this as the ‘glossy mag headline.’ Next time you’re out and about, take a look at what’s on the magazine covers. Positive messages might be nice, but messages about mistakes sell more.
What negative aspect of your industry can you highlight in your subject line?

Try ‘Bad {your industry} Advice’

9. Subject line: It finally happened

  • Sender: ProductHunt
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Wait, what finally happened? Is it good? Bad? Am I affected? Turns out it only takes three words raise your reader’s heart rate, along with their curiosity.

10. Subject line: Answers and Mistakes

  • Sender: Lincoln Murphy
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

We all want answers, and we have an insatiable appetite for seeing other people’s mistakes (remember the ‘glossy mag’ principle?). The subject is direct and to the point, and for those on Lincoln Murphy’s list it will create enough curiosity among his readers to get them clicking.

11. Subject line: Increase your productivity with ROBOTS!

  • Sender: ProductHunt
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Like my aversion to all lower caps sentences, I’m normally against SHOUTING ALL-CAPS. But when you have a cool topic like robots, I think that’s something worth shouting about. Product Hunt offers a clear value proposition (increased productivity) with a dash of the unexpected (robots).

12. Subject line: {Your Name} in 2017!

  • Sender: Ed Gandia
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

This is an example of a subject that uses personalization in a succinct format. This was sent shortly after the start of the year, when virtually everyone was thinking about what the next year held for them.
Remember that sometimes when in the year you send your email can have as much an effect as what you send.

13. Subject line: You are not alone

  • Sender: Leah @ FTFP
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Sean Platt has written a post on CopyBlogger on how this is his most-opened subject line by far. The post is well worth a read, but the gist is that we all share a need to belong, to not be alone. That makes this a compelling subject line, and one that will speak to the hearts of your reader, whoever they may be.

14. Subject line: Circle this date and preorder the champagne

  • Sender: Donald Miller, StoryBrand
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Donald Miller uses this subject to elicit the recipient’s interest. Rather than simply stating that an important date is coming up, he finds a fresh interesting way to illustrate how important it is.
Taking the time to find new and different ways to make announcements ensures they don’t grow stale.

15. Subject line: Uber for Dogs

  • Sender: CBInsights
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

We’ve considered controversial statements as subject lines, but here we have an example of the bizarre. The line makes the mind boggle, and curiosity makes you click to find out more.
To keep your audience happy, make sure the email delivers on the promise.

16. Subject line: [Classified] Secret Project…

  • Sender: Kai Davies
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

From the bizarre to the mysterious.
Maybe it’s too much time watching James Bond films, but when this showed up in my inbox there was no way I couldn’t click on it.
Involving your recipients in something exclusive and mysterious will pay off in higher open and click-through rates.

Asking a Question

The quickest way to get someone’s attention is to ask them a question. There are two reasons why questions work so well as subject lines. First, unlike a statement, a question does not just say something, it interacts with you. Second, when you are asked a question, your brain automatically begins to try to think of an answer.

Here are a few examples of this mechanism in action:

17. Subject line: How do you plan to scale?

  • Sender: Nick Stephenson
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

Asking a question is the simplest way to create curiosity, and this is an example of it done well. The sender could have asked ‘Do you plan to scale,’ a question with a straightforward yes/no answer. Instead, he asks ‘How’ you plan to scale. The question requires more thought, as well as implying that the reader should already have a plan in place.

18. Subject line: Content Strategy: Is Your Content a Mess?

  • Sender: Clearvoice
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

‘You’ is a magic word in marketing, and Clearvoice gives us a classic example. Using ‘your’ in their subject lines elevates the service offered or the problem highlighted to something specific to the recipient. We’re not hearing about random people’s content issues, but our own, and that’s always more powerful. The second subject also used the power of fear, a strong motivating factor to take action.

19. Subject line: Stuck in a Facebook ad rut?

  • Sender: Jo at Copyhackers
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

This email works by appealing to the recipient’s problem, rather than the promise of a solution. If a recipient is experiencing this problem, if they look at the subject line and say ‘Yes, yes I am,’ then they’ll be more likely to open the email.

20. Subject line: How can I help?

  • Sender: Kai Davies
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

When so many emails are all about selling, an email that’s completely focused on offering help (with no costs or strings attached) stands out. The sender gets to know what problems affect their audience, as well as form closer relationships with prospective customers. The recipient gets free help and advice. A win/win, and a subject line that will quickly get your email opened.

21. Subject line: Need help?

  • Sender: Ed Gandia
  • Type: Inbound Opt-in
Dmitry
Dmitry and Lucy's take

A more brief version of the example above.

22. Subject line: How many stars would you give ‘{recent purchase}’?

  • Sender: Amazon.co.uk reviews
  • Type: Customer
Dmitry
Dmitry and Lucy's take

Reviews are an important aspect of Amazon’s business; how many times have you bought something there without checking the reviews? However, getting people to actually leave a review isn’t that simple. To increase the likelihood of someone leaving a review, Amazon starts off with a subject line that asks you simply how many stars you’d give a recently bought item, rather than to leave an entire review. If you must ask for something with your email, make it a small ask, something the recipient can easily say yes to.

23. Subject line: Time for a career change?

  • Sender: Tough Mudder
  • Type: Customer
Dmitry
Dmitry and Lucy's take

While Tough Mudder put on obstacle races around the world, they also know their audience are people who are up for some adventure. That’s why when they’re looking for potential employees, they’re able to use subject lines like this to appeal to their own audience, people who by definition would be ideal potential candidates.

24. Subject line: How’s it going with Calendly?

  • Sender: Calendly
  • Type: Customer
Dmitry
Dmitry and Lucy's take

Have you ever been out for a meal and had the waiter ignore you after taking your order? Instead, they’re normally around after a few minutes to check everything’s okay. Calendly follow this pattern, making sure their customers are happy with the service so far.
It’s a great opportunity to get feedback and make sure customers are getting the best from them, and the subject line is direct and to the point. Being sent soon after signing up (but after enough time has passed for the customer to try out the service) along with an easy-going informal tone all contribute to massive open rates.
What do your customer follow-up emails look like?


Try using ‘How’s it going with {your product/service}?’

Social Proof

In an ideal world, people would make purchases by evaluating a product rationally. But you know that happens only in economics textbooks. In the real world, people make decisions based on social proof – what are other people saying, doing and buying.

People want a quick way to validate that the offering works and the easiest way to do that is to follow the lead of others who have already used it. Social proof is one of the most powerful persuasion triggers used by marketers.

25. Subject line: Lucy, join over 24,000 businesses funding their next step

  • Sender: Funding Circle
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

Funding Circle use personalization by referring to the recipient by name, then adds social proof to grab the reader’s attention. If it’s good enough for 24,000 businesses, surely it’s worth checking out? Using ‘join’ as a verb is also a good move, inviting the reader to be a part of a large community of businesses.

26. Subject line: #1 rated overall for home security

  • Sender: Protect Your Home
  • Type: Outbound
Dmitry
Dmitry and Lucy's take

This straightforward subject line focuses on the social proof that this system is the ‘#1 rated overall.’ If your service or product has been given any awards or ratings, then highlighting them in the subject line can convince recipients to open up to learn more.

27. Subject line: Thousands join this webinar every month. Why haven’t you?

  • Sender: Sumo
  • Type: Inbound Opt-in
Dmitry