100 Cold Email Subject Lines To Guarantee a Response

Dima s
Dmitry Dragilev Last updated on August 10, 2017 One Comment

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 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:

1. Subject line: Are You Prepared for This?

  • Sender: JivoChat
  • Type: Outbound
  • Dmitry and Lucy’s take: This subject raises curiosity 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 fear of not being ready for an important event.


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

  • Sender: WorkRails
  • Type: Outbound
  • 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 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 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 and Lucy’s take: 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 and Lucy’s take: This subject line is similar to the example above.


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

  • Sender: Amazon.co.uk reviews
  • Type: Customer
  • 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 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 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 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 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 and Lucy’s take: Sumo calls out people on their mailing list who haven’t taken advantage of their monthly webinars, while also using social proof (thousands attend this webinar, so it must be useful). By framing it as a question, your brain engages with the subject line, wanting to fill in an answer.

28. Subject line: “Products the celebs are wearing”

  • Sender: Sephora
  • Type: Opt-in
  • Dmitry and Lucy’s take: In the cosmetics world, people would always look for inspiration from celebrities – they are the ones setting the trend. To use this in your industry, figure out who people look up to for inspiration and mention the approach those influencers are taking in your subject line. If the influencers are doing something, it’s important enough for you to open the email and have a look!



Straightforward subject lines tell you what the email is about. No mystery or advanced psychological tactics are involved. And yet they work, because they offer a compelling benefit for a particular persona.

However, this type of subject line will have no influence on someone who does not fall within that persona.

29. Subject line: Ad reporting product – feedback

  • Sender: OmniLabs
  • Type: Outbound
  • Dmitry and Lucy’s take: This subject is a little more direct and to the point than some of the others on the list. If you try and get too clever with your cold sales email subject, you may just get your email deleted. The sender has done enough homework to know that an ad reporting product would be of interest to the recipient, which is the key task with an email like this. With cold emails, sometimes you just have to spell out what you’re offering.


30. Subject line: Capturing attention

  • Sender: TheAnimationSolution
  • Type: Outbound
  • Dmitry and Lucy’s take: A two-word value proposition that does what it says on the tin: captures attention. With a ‘less-is-more’ vibe, the deal is that if you want to know more, you’ll have to open the email. If you’re going to use this method, make sure the subject is definitely something your recipient wants to know about, or they won’t be curious enough to continue.


31. Subject line: Intent data for Reply

  • Sender: Kickfire
  • Type: Outbound
  • Dmitry and Lucy’s take: Personal cold email subject lines are a powerful technique in marketing and Clearvoice give us a classic example. Rather than just simply using the company name, this subject promises something (in this case intent data) that’s specific to the company, making it vastly more valuable to the recipient, and worth their time to check out.

32. Subject line: Announcing Goal Tracking for Marketers

  • Sender: AutoPilotHQ
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: If you’re going to announce something, make sure it’s something that the recipient will give a damn about. By introducing a feature with obvious benefits that will appeal to their audience, as well as spelling out who it’s for, AutoPilotHQ makes sure this email will be read by their target audience.

Try using ‘Announcing {Awesome feature} for {Recipient Job Role}’


33. Subject line: The Scariest Places in the World

  • Sender: Conde Nast Travel
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Conde Nast Travel’s subject may come across as another fear based line, but actually this email is appealing to the adventurous side of their typical audience member, those who are may be more inclined to go off the beaten path. This isn’t so much ‘avoid’ as ‘visit if you dare.’
    To emulate this subject, think about what your audience believes that others may not. What would inspire them that would scare others?


34. Subject line: The Best Carry-On Luggage

  • Sender: Conde Nast Travel
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is an example of knowing your audience and what they search for. Whereas many subjects ask a question, this answers one instead. If your subject line answers a question your audience is asking, they won’t be able to open your emails quickly enough.
    A great way to find subjects like this is to take a look at your analytics and see what search terms are bringing people to your site, or sites similar to yours. What answers are your audience searching for?


35. Subject line: Re: Reply’s influencer program

  • Sender: GrowSumo
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: GrowSumo offers you information on your influencer program, using a similar method to Clearvoice. They take the personalization a step further and uses the recipient’s company name. It’s also worth noting the use of Re: on their follow up emails, a little touch that helps the email stand out.
    I’d use this with caution though; I’ve seen this used on cold emails and though I may have opened the email, I ended up feeling tricked, and certainly didn’t click through. Nobody likes to feel tricked.

36. Subject line: Your Content Vision Review

  • Sender: Clearvoice
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: One way to get insanely high response rates in cold emails is to research the prospect well enough to be able to make a custom recommendation. For instance, can you review something about the prospect’s content strategy, their website or any other visible aspect of their business and send them a report? That would make a highly favorable impression significantly improve your chances of getting the deal.


37. Subject line: Your weekly progress report + tips

  • Sender: Grammarly Insights
  • Type: User
  • Dmitry and Lucy’s take: Grammarly helps keeps their users engaged with their weekly emails. By giving detailed reports on your progress (as well as comparing those results to other Grammarly users) and tips for improvements, they make what could be a bland marketing email something useful and interesting to their users.
    Can you use direct customer data to expand the personalization of your subject lines?

38. Subject line: {Your Name}- Hard Work Pays Off and You Worked Hard

  • Sender: BodySpace
  • Type: User
  • Dmitry and Lucy’s take: The fitness app offers weekly personalised summaries of workouts and progress, as well as reminding you when you haven’t exercised.


39. Subject line: See who liked your page

  • Sender: Facebook
  • Type: User
  • Dmitry and Lucy’s take: Facebook has more active users than any other social network, completely dominating the competition. One of their methods for keeping users active is by using subject lines like this, to keep the curiosity factor high. Who wouldn’t want to know more about the people checking out your page? What information is your audience going to find compelling?


40. Subject line: Instapage + Zapier for super powers ⚡

  • Sender: Instapage
  • Type: Customer
  • Dmitry and Lucy’s take: The sender has done a great job of jazzing up a fairly standard subject line (‘A’+’B’ for great results) and made it stand out by describing the result as super powers, with a funky little emoji. Which would you prefer, great results or super powers? By talking to them as a friend rather than sounding like a tired out sales letter, your recipients are much more likely to open the email.



Offers are very similar to straightforward subject lines with one difference – they are also promotional. An offer based email with either try to make a sale or give you something valuable for free.

Offer subject lines work won’t work unless the sender is known to the recipient.

41. Subject line: Your Next Beach Destination

  • Sender: BookingBuddy
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This isn’t about random destinations; these are your next beach destinations. And as most of us spend a large percentage of the time at the computer daydreaming about getting away from it all to some sunny beach, this is likely to get opened.
    What if you’re not selling beach holidays? Use your list’s behaviour to offer repeat services.


42. Subject line: 20% off your order! (These savings are to dine for…)

  • Sender: West Elm
  • Type: Outbound
  • Dmitry and Lucy’s take: A clear and obvious value proposition, but your inbox is likely flooded with companies offering you money off your order. A clever bit of wordplay helps it stand out though. Remember, if you get your recipient to smile, they’re much more likely to open your email.

43. Subject line: How do you reach new customers? Try Google AdWords today

  • Sender: Google AdWords
  • Type: Outbound
  • Dmitry and Lucy’s take: Google uses a desired outcome/solution combo to hook readers. By using a question to highlight something that every business on the planet is interested in (new customers), they then answer that question with their own service. That added ‘today’ encourages recipients to act on the email now, rather than put it off to an uncertain future date.


44. Subject line: Choose your stand at the M.A.D.E.

  • Sender: M.A.D.E. 2018
  • Type: Outbound
  • Dmitry and Lucy’s take: Rather than informing potential customers that stands are available, or asking whether they would be interested in attending, this email asks them to choose what stand they’ll have. The technique is an effective method of increasing the chances of a positive response.

45. Subject line: Special Offer for Lucy

  • Sender: HubSpot
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Sending special offers to your email list is a practice as old as marketing itself, but that doesn’t make it any less powerful. Thanks to the well-known sender and the fact this is for an opt-in list makes it easy to open. As with the outbound examples, I’d still be cautious of overusing if you want to keep those high open rates. By definition, special offers shouldn’t be a common occurrence.


46. Subject line: See What You Can Do For Under £25!

  • Sender: Groupon Under £25
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: By knowing their audience (people who love a good bargain), Groupon appeals directly to them and their wants. Rather than focusing on the specific products/events on offer, they use the subject to draw attention to the affordable nature of the deals. Knowing your recipient’s wants and needs will help you come up with compelling subject lines.


47. Subject line: 🎁 Your Complimentary Pass to INBOUND 2017

  • Sender: Hubspot
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: By offering something of value for free, you’re going to get attention. Of course, as more people offer more for free, you have to go further to stand out. Hubspot’s does this through their positioning as a respected authority and offering complimentary tickets to a major, in-person event.


48. Subject line: 🏫 Master Class Invitation for {Your Full Name}

  • Sender: Hubspot
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

49. Subject line: Fancy a movie on us?

  • Sender: Three Mobile
  • Type: Customer
  • Dmitry and Lucy’s take: Three, a mobile service provider in the UK, give a value offer (a free movie), but, in line with their brand, they abandon any stilted language. Instead, their subject line is much more informal and chatty, fitting right in with the emails from your friends and family.


50. Subject line: ⚠️ Lucy Your Special Code Is Inside! ⚠️

  • Sender: Saltrock
  • Type: Customer
  • Dmitry and Lucy’s take: Like me, you probably get emailed about different sales and offers every day. Surfwear seller Saltrock has made their promotional email stand out by personalizing it, referring to the recipient by name and making the offer specific to them (a unique code). Additionally, they’ve used emoji’s to make the message appear more important.

51. Subject line: Start sending your leads to one of these integrations

  • Sender: Instapage
  • Type: Customer
  • Dmitry and Lucy’s take: A well-crafted subject line is clear on the contents of the email, while still leaving questions in the reader’s mind. In this case, it’s clear that you’re going to read about specific integrations to use as part of your lead funnel, but what integrations? You’re going to have to click to find out.


52. Subject line: Learn how to stop losing app customers. Attend this VB Live event!

  • Sender: VentureBeat
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

53. Subject line: Get a head start on summer

  • Sender: Topshop
  • Type: Opt-in
  • Dmitry and Lucy’s take: This type of subject is all about timing. Many people will want to know which fashion trends to follow in summer right before it arrives. What will your audience be interested in during a certain point in time, or during a certain time of the year? Answer that question and give them a way to get a head start. They will open it because you are right on time!


Numbers Based

Using a number in a subject line is a powerful psychological trigger. The moment you add a number to a statement, you make it more credible and specific, and therefore people become more interested in knowing more about it. Adding percentages and dollars make subject lines even more compelling!

54. Subject line: $21,000 Extra Revenue Per Month

  • Sender: TheAnimationSolution
  • Type: Outbound
  • Dmitry and Lucy’s take: Cold email subject lines with specific numbers are an effective method of drawing attention, and better than using vague approximations. It indicates that you’ll receive specific information in the content, rather than wishy-washy advice. Usually you’ll find the bigger the number, the bigger your headline.


55. Subject line: Who spends 61% of their time managing work?

  • Sender: Dropbox
  • Type: User
  • Dmitry and Lucy’s take: This email works by asking a question, a common tactic, but also uses the odd number to stand out. 61% is a very specific number, rather than a rounded ‘over 60%.’ Ignore the temptation to round your numbers up or down in your email, and try using more unusual numbers in your subject.


How to

Emails with ‘How to’ subject lines will provide you with a solution to a problem or an objective that is important to you. These emails work just like content marketing does – by educating prospects about a particular topic and winning their trust, before trying to sell.

This can be an extremely effective approach for building rapport in a cold email campaign.

56. Subject line: Stealing Your Competition’s Customers

  • Sender: GrooveHQ
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line has a great word choice. It sounds almost criminal, which is exciting for the recipient. It appeals to a more mischievous mindset, making the reader want to learn more, while also possessing a clear value to the recipient.


57. Subject line: How To Eliminate Doubts And Make Everyone Want What You’re Selling

  • Sender: SeoPressor.com
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: The ‘How to do A and achieve B’ is a classic and effective format, echoing the famous book ‘How to make friends and influence people.’ In the information age, being able to teach people how to do something and achieve the desired result is a valuable skill, and one you should be willing to spell out in your email subjects.


58. Subject line: Get your crowdfunding campaign funded

  • Sender: Sumo
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Using the same principle as above but in a different format, Sumo’s email promises to help the recipient achieve the desired result (the funding of their crowdfunding campaign). A clear promise of a valuable benefit will get your email opened by the right people.


59. Subject line: Nobody wants your newsletter, but they do want THIS

  • Sender: Donald Miller, Storybrand
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.


60. Subject line: Blinkist Minute: How to be exceptional

  • Sender: Blinkist
  • Type: Customer
  • Dmitry and Lucy’s take: Blinkist provides summaries of non-fiction books and their daily emails are similarly concise. They’ve mastered the art of capturing the key benefit of a book and spell this out in the subject line, letting you quickly know if it’s worth your time reading. Who wouldn’t want to be exceptional?


61. Subject line: Use this PDF whenever you meet with a prospective client

  • Sender: Brennan Dunn
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject works by quickly establishing what you’ll receive in return for opening the email. A tool (in this case a downloadable PDF) that you can use for a specific, important situation (meeting with prospective clients).

62. Subject line: Age-defying beauty tricks

  • Sender: La Mer
  • Type: Opt-in
  • Dmitry and Lucy’s take: The subject talks about a problem and a solution in just four words. It also does a great job of making you curious – one of those situations where you can’t help but take a minute to see what those tricks are. Doesn’t matter if you have read tons of similar emails/ articles before. If it matters to you, you will want to open it and see!


Numbered Lists

One of the most popular article formats is the list post. People love to check out a list of tips or recommendations and that’s why these also work very well in subject lines.

This is similar to ‘How to’ subject lines because they also try to provide information that is useful to a particular persona and build rapport before trying to sell.

63. Subject line: 5 Ways to Increase Engagement on Instagram

  • Sender: Convince & Convert
  • Type: Outbound
  • Dmitry and Lucy’s take: There’s a reason you’re reading a post on the 100 best cold email subject lines. Numbered lists have a long history of drawing views, and using them in a subject line is a good way to quickly give readers an idea of what they can expect.


64. Subject line: The 4 Best iPhone Apps for Entrepreneurs

  • Sender: Business Advisor
  • Type: Outbound
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

65. Subject line: My 5 favorite posts ever

  • Sender: OkDork
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Another example of an effective ‘list’ style subject line. The difference here is that for a warm email list, they are more likely to actually care about what your favourite posts are. Sending this exact line to a cold list would flop; However, for an inbound list, this is a great way to utilize and build on the existing relationship between the sender and the recipient.


Scarcity/ Urgency/ Exclusivity

Retail outlets sell more during a sale then during any other time of the year.  That’s because scarcity has an unusually compelling effect on our brains. It often works when nothing else does.

When we know that something is being offered during a limited time, is available in limited quantities or is exclusively available only to a select group, we immediately attach a higher value to it.

66. Subject line: I didn’t want you to miss out on this…

  • Sender: Hubspot
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Nobody likes to miss out, and the conversational tone (‘I’ instead of ‘We’ or ‘Hubspot’ and ‘you’ instead of ‘people’) makes this feel more like an email from a friend than one from a company to a list.


67. Subject line: Limerick has some last-minute deals!

  • Sender: Booking.com
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

68. Subject line: Private Invite to [:] {Event}

  • Sender: VentureBeat
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: A private, exclusive invitation is a lot more exciting than an e-blast to thousands on an email list. The difference is semantic, but by making a recipient feel special, they’re more likely to give a favorable response.


69. Subject line: 7 seats left (ends today)

  • Sender: Brennan Dunn
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: As a follow-up email to the announcement of an event, this one uses scarcity of availability to motivate the reader to click through and take action. If they don’t act soon, at least by the end of the day, then they’ll miss out.

70. Subject line: 3 items from your Steam Wishlist are on sale

  • Sender: Steam
  • Type: Customer
  • Dmitry and Lucy’s take: Anyone who uses Valve’s Steam service for downloading and playing PC games will be familiar with this subject line, especially during their regular massive sales events. If you have a site with a ‘wishlist’ feature, are you using it to inform potential customers when something they want is on sale? This is a great example of following up when the customer has told you something specific they’re interested in.


Fear/ Inability

Numerous studies have validated that the prospect of losing something is a far bigger motivator than the prospect of gaining something.

These subject lines tap into your fear of losing something, or your inability to get something done and compel you to open the email and see exactly what is it that you are at risk of, what the extent of the risk is, and see if there is a possible solution.

71. Subject line: Bad news, nobody wants to read your newsletter

  • Sender: Donald Miller, StoryBrand
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Donald Miller literally starts this subject with bad news, and again uses strong words to emphasize the importance of the email. Rather than saying some people don’t want to read your newsletter, the subject states categorically that nobody does. A great example of using a negative style subject to raise interest.


72. Subject line: 3 things that need to happen before you can win more projects

  • Sender: Brennan Dunn
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: The use of ‘need’ increases the perceived value of this email. We’re not talking about something optional; If you’re not doing these things, you’re not going to win more projects. The fear of missing out on essential information acts as the motivation.


73. Subject line: Hello Lucy – Why High Performing Talent Are Choosing Your Competitor & What to Do About It!

  • Sender: Sigma Recruitment
  • Type: Outbound
  • Dmitry and Lucy’s take: While this is the longest subject line in the list, it still uses a number of principles that make it effective. Along with personalization of the recipient’s name, the subject uses fear-based motivation (talent are choosing your competitor over you) and promises a solution if you click through to open.

74. Subject line: Important Insurance Information

  • Sender: Denovo Risk Solutions
  • Type: Outbound
  • Dmitry and Lucy’s take: When it comes to essential services like insurance, people don’t want to risk missing out on important information. While it could potentially come across as misleading, in this case the content of the email quickly made clear important changes to insurance that would be of interest to businesses in their target market. If you have important information to share, then declare it in your subject line. Just make sure it actually is important, lest you annoy the recipient.


75. Subject line: Are your food safety practices up to standard?

  • Sender: SAI Global
  • Type: Outbound
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

76. Subject line: your growth hacks aren’t working

  • Sender: Close.io
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Here’s another subject line that uses fear as a motivation, personalized to the reader. The strong tone also helps. For example, they haven’t said ‘why your growth hacks might not be working.’ The subject line is a definite statement and motivates the reader to take action.

Try out ‘Your {key strategy} isn’t working.’


77. Subject line: You’re missing out on points

  • Sender: Jetblue
  • Type: Opt-in
  • Dmitry and Lucy’s take: A classic example of using FOMO (Fear of Missing Out) as a trigger. Nobody want to miss out on an opportunity. That usually explains why people with no shortage of money go after limited period deals.
    The most effective way to use this is to figure out what your persona values. Then insert that goal or desired object into the subject line: You ‘re missing out on______ .
    For instance, if you are targeting marketers try: “You are missing out on Traffic”


Case Study/ Concrete Example

This is the most powerful type of ‘How to’ subject lines. Nothing is better than a case study or a concrete example of something actually being done.

Equally compelling are statistics that give you valuable insights for making important business decisions.

78. Subject line: How Marketo reduced churn and grew their customer accounts

  • Sender: InsideView
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Direct and to the point. Marketo is one of the best known names in the Marketing SaaS space. People in account management roles or at a top management level at a SaaS company would certainly want to know what they did right.


79. Subject line: Inside a $50 million startup

  • Sender: OkDork
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: We’ve already seen how using high, specific numbers can be an effective method of increasing open rates in cold emails. These can work even better for a warm contact list, where the recipient is already familiar with you and your company. That familiarity provides a context for the figures and increases confidence that the information is legit.

80. Subject line: Acquired for $3.7 Billion

  • Sender: TractionConference
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Who got acquired? How? That’s what will go through your mind when you see this subject line. If you are in the startup space. You will click. $3.7 billion is certainly a very large number and people will want to know what the company did to attain this incredibly high valuation.


81. Subject line: Getting to 500 Million Users

  • Sender: TractionConference
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Another compelling subject line for most startups. 500 million is a huge number and all startup folks would want to steal an idea or two from the company who’s been there and done that!


82. Subject line: $4940 for a weekend’s work

  • Sender: Sophie Lizard
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: As well as using specific, impressive numbers, these examples also promise a bit more for the reader, with an unspoken promise they’ll be able to learn from these and hopefully achieve the same results in their businesses.


83. Subject line: [Case Study] How We Ranked #1 for a High-Volume Keyword in Under 3 Months

  • Sender: CriminallyProlific
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: The subject starts with a clear description of what readers can expect (a case study), then follows up with a ‘How to’ style subject, centred on a goal their readers will be interested in (ranking number one for a high volume keyword), and includes a time frame (under 3 months). The value proposition is really clear, and anyone looking for higher search engine rankings will have to click through.


84. Subject line: ✉️ [Case Study] How Reply Helped Generate a $400,000 Revenue Pipeline

  • Sender: Reply.io
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

85. Subject line: The 5 line pitch that has generated millions in sales copy

  • Sender: Ramit Sethi
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: In this email, Ramit Sethi creates a sense of mystery, but while still being clear on what’s in the email (an example of a pitch) and why you should care (it generated millions in sales copy).
    It can be broken down as: The [something your prospect needs] that [specific value it provides].
    Be careful about too much mystery; unless you’ve already built up sufficient trust with the recipient these can look like spam.


86. Subject line: The Briefcase Technique (virtually guaranteed to land clients)

  • Sender: Ramit Sethi
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject line is similar to the example above.

87. Subject line: The state of email marketing (it’s weird)

  • Sender: Sumo
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: The last two words make this subject line. The state of email marketing sounds like a potentially bland, boring subject, but by adding that ‘it’s weird’ instantly makes it a more interesting subject. We’re promised this is going to be something different, something unconventional.


88. Subject line: Here’s my complete marketing roadmap

  • Sender: Donald Miller, StoryBrand
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This email works by emphasizing the value of the content. This is a complete marketing roadmap and used by the person sending the email, so you know it must be good. When you’re offering something of value, highlight the value to your audience with the language you use.


89. Subject line: How Watson AI is getting marketers real ROI

  • Sender: VentureBeat
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This subject uses a couple of methods to attract readers: First of all, it refers to something of current interest to the target audience of marketers. It may be something they’ve heard of, but don’t know much about. It also includes reference to ‘real ROI,’ spelling out the value to the reader of clicking through and learning more. While the specific subject isn’t evergreen, it can easily be adjusted by referring to industry news specific to your audience, along with a motivating reason to learn more.


90. Subject line: Projects we love: Heart and Soul

  • Sender: Kickstarter
  • Type: Customer
  • Dmitry and Lucy’s take: Kickstarter draw previous contributor’s attention to interesting projects, but their use of language moves beyond a bland ‘you might also like.’ Instead, they talk about projects that they love. The passion is infectious and encourages readers to click through and learn more about the project.

91. Subject line: How to email a busy person (including a word-for-word script)

  • Sender: Ramit Sethi
  • Type: Opt-in
  • Dmitry and Lucy’s take: We are always looking for templates. Why try to reinvent the wheel when you can just use something that’s been proven to work? To use this, make a value proposition that makes it super-easy for your prospect to do something. The effort to read the email should seem miniscule compared to the benefit that they would get.


92. Subject line: Steal these email templates…

  • Sender: Digital Marketer
  • Type: Opt-in
  • Dmitry and Lucy’s take: This example is very similar to the above, with one difference. By using the word ‘steal’ they are emphasizing that it’s too good to be true! You are essentially getting something priceless, for practically nothing!


Personal Story

Personal stories draw you by humanizing the sender. They make you look more like a real person rather than an unknown random entity.

Some of them might be similar to case studies, but aim to make a connection through a more human experience rather than through data. They are a great way to establish rapport.

93. Subject line: What two ex-girlfriends taught me about sales

  • Sender: OkDork
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This one made me smile, and a subject line that makes your recipient smile is one they’ll open. On the opposite side of the scale from $50 million startups, OkDork switches to a story hook about ex-girlfriends, but with the promise that you’ll learn something about sales. This makes for an effective combination.


94. Subject line: How An Angry Email Pushed Us To Start Publishing More Product Updates

  • Sender: GrooveHQ
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: This is a high curiosity subject, one that raises lots of questions in the recipient’s mind. What was this angry email, what were they angry about, what are these product updates? There’s a story here that’s much more effective than simply stating that the company is publishing more updates.


95. Subject line: Why I Stopped Hustling

  • Sender: GrooveHQ
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: In a world that praises constant hard work and hustle, the email challenges the reader with an unexpected subject, one that may be opposite to their preconceptions, and promises a story. The unexpected will always stand out from the familiar.



News articles always get the most eyeballs. Anything that’s just happened or is still happening is always interesting because we have an instinct to stay in touch with what’s going on – something that was vital for our ancestors’ survival.

Try talking about a bit of news that is very relevant to your persona, and you will have a high open rate.

96. Subject line: Alphabet offloads its risky robot bet

  • Sender: TechCrunch
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Another robot subject, but not in all-caps this time. This still works though, as it’s using a well-known company in the headline, and arouses curiosity with the mention of a risky bet. The misfortune of others is always something people will be interested in.


97. Subject line: What, exactly, is going on at Google?

  • Sender: CBInsights
  • Type: Newsfeed
  • Dmitry and Lucy’s take: A good use of curiosity and conversational tone help this subject line. The tone takes on a water-cooler, gossipy feel, and we all love a bit of gossip. Whether you know what’s going on at Google or not, you’re likely going to want to click through and find out for sure.

Try ‘What, exactly, is going on at {relevant industry leader}?’


98. Subject line: Uber’s really bad idea

  • Sender: CBInsights
  • Type: Newsfeed
  • Dmitry and Lucy’s take: Another ‘glossy mag’ subject line. When we’re told that a well-known and successful company like Uber have had, not just a bad idea, but a really bad idea, it grabs your interest. It’s important that the company is well known to generate enough curiosity. Some unknown, unheard of company’s mistakes aren’t nearly as interesting to the average reader.

Try ‘{Relevant industry leader}’s big mistake.’


99. Subject line: another day. another unicorn.

  • Sender: CBInsights
  • Type: Newsfeed
  • Dmitry and Lucy’s take: Spinning familiar sayings in unexpected ways can help your personal email subject line stand out. While I’m not a fan of the all lower case spelling, the play on ‘another day, another dollar’ is enough to grab attention.
    If you want to try this for your own email campaigns, have some fun brainstorming common sayings with keywords for your industry (in this case unicorns, or business startups valued at over $1billion).



What gets more eyeballs than news? A controversy.

Do this right and you certainly get lots of opens. However, be careful not to use subject lines that might be too controversial or might be offensive to a group of people. That might seriously backfire.

100. Subject line: Motivation is garbage

  • Sender: Leah @ FTFP
  • Type: Inbound Opt-in
  • Dmitry and Lucy’s take: Similar to the negative focused subject lines, this one uses a controversial statement to grab attention. How does it make you feel? Do you agree? Disagree? Either way, you’re likely to click through to find out why the sender has this opinion, either to confirm your own belief or to prove them wrong.
    Be careful that the statement isn’t so controversial it would insult your audience though.


There you go, 100 examples of effective email subject lines.

Going through them you no doubt have noticed recurring patterns:

Effective subjects will typically create curiosity, usually by asking questions or making unusual/counter-intuitive statements.

They will also often be personalized to their audience, either by using the recipient’s name or company name or by referring to issues and problems specific to their industry.

They’ll also regularly demonstrate a clear value proposition for the reader, assuring them this is worth their time and giving them a compelling reason to open the email.

By studying these examples and using one or more of these principles, you can be sure that you’re subject lines will appeal to your reader and will increase your open and click-through rates.

One thought on “100 Cold Email Subject Lines To Guarantee a Response

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    Thanks for sharing this amazing article with us. This post is really very informative.

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