50 best cold email subject lines

The 50 Best Cold Email Subject Lines for 2023

Over 300 billion emails are sent each day. Most of them stay unopened. Even a well-written and useful email can go unopened unless its subject line is amazing.

Every time you plan to send an email to a prospect, a client, a company, etc, take into account that your subject line is the key to whether your email will be opened, ignored, or marked as spam.

Recent studies have shown that over 60% of people mark emails as spam due to the subject line only. In other words, your email subject line should be powerful enough to break the ice and make the recipient open and read your email.

How to Write Powerful Email Subject Lines

Here I’ll cover our best tips and tricks on how to create powerful and catchy subject lines to 10X your open rates. 

Keep it Short and Sweet

The ideal length for a standard email subject line is 30-60 characters. 

Keep in mind that most of the recipients check their inbox via mobile so your subject line should be short enough that they can read it. 

According to Convince & Convert, 82% of marketers send emails with subject lines not exceeding 60 characters.

Use Targeting and Personalization

Sending relevant and targeted content to your subscribers is easier when you segment your contacts into sub-lists. You can group contacts according to attributes like geographical location, age, job position, content preferences, or how often you would like to contact them.

You can create different subject lines for each segment of your email list once you have defined them. This results in a more targeted message and, more email opens.

Content can be tailored even further with email personalization. Your email will stand out from the crowd if you include subscribers’ first names in the subject line.


Using ALL CAPS in your email subject lines makes your chances of getting to the recipient’s spam list higher than ever.

According to Campaign Monitor, using ALL CAPS in the email subject line brings zero opens and higher chances to be marked as spam. So, be careful and avoid using this. 

Try to Sound Human-like

It is crucial for any email communication to sound natural and human-like to catch the attention of the recipient. It makes clear to the readers what your email is about. Even if your company is too serious, complex and robotic sentences won’t be perceived well by your audience.

Use Emojis

Using emojis in your subject line is always a good idea. They make your subject line more catchy and fun. The properly chosen emoji can significantly increase the readability of your email.  The open rate of emails that include the subject line is 56% higher than those with plain subject lines.

To add emojis to your email subject lines, you can use Emojicopy or Emojipedia. Just type what you want, copy the emoji then simply paste it into your editor. 

Perform A/B Testing

You can never know which subject line works the best unless you perform A/B testing. The logic of the test is simple: just send the same email with the same subject line to small amounts of accounts in your list. Then, track which group opened the email and interacted with it more often. Now, you can send the winning email to your whole list.

Best subject lines for cold emails to use in 2023

There is no question that subject lines have become a decisive factor in whether your email will be read. Here we have organized the best-performing cold email subject lines that you can use to break the ice and get more winning email campaigns in 2023.

Subject lines with questions

Subject lines with questions work perfectly. They invoke an urge for finding answers. 

It is most effective to ask questions related to goals and pain points in the subject line. It is likely that prospects will open your email because they’re curious to find out what doubts you have about their goals, and how you can help them.

1️. Quick question

2. About {company name}

3. ☕ Coffee this week?

4. {their company} {your company} Collab?

5. Partnership?

Personalized subject lines

Recent studies state that recipients are 26% more likely to open emails with personalized subject lines. So why personalization is efficient? The answer is simple. When you hear or see something related to you, your brain shifts focus almost immediately. Humans behave instinctively in that way.

Your subject lines should communicate to your prospects that this is about them and for them.

6. Congrats on the promotion {recipient name} 🎉.

7.⭐{recipient name}. Loved your post on {social media platform}.

8. 🤫{recipient name}, you don’t want to miss this.

9. Quick video for {recipient name}. 

10. Is this a good time {recipient name}? 

Short subject lines

More than half of people read emails via mobile devices. This is why it is important to keep your subject line as short as possible. The most important thing here is to make the subject line meet your main needs. 

11. 🤩 Meet {product name}. 

12. Don’t miss out. 

13. 🔥 Are you ready?

14. Potential cooperation.

15. Trying to connect.

16. Open position

17. Solution for {problem}

18. Guest post request.

19. Request for feedback.

20. 🎉It’s official.

21. You are invited.

Mutual connection subject lines

These subject lines are super efficient. 

By mentioning a mutual connection in the subject line, you increase the chances of someone opening your cold email. 

Consider mentioning the prospect if you have a mutual acquaintance. Attending the same events and or being an alumnus of the same school or university also increases the chances that your email will be opened and read. So, don’t hesitate to mention that in your email subject line. 

22. {mutual connection name} suggested I reach out to you.

23. I am reaching out by {mutual connection name} recommendation. 

24. I hope you enjoyed {event name}.

25. 👋Hi from a {common college/university name} alumnus.

26. Do you know {mutual connection name}?

27. Enjoyed your seminar {event name}.

28. Was nice meeting you at {event name}.

29. Hey, fellow {sport or hobby name} fan!

30. {mutual connection name} said great things about you.

31. How about playing {sport name} next weekend?

Subject lines with humor

Subject lines with humor can also increase your open rate. However, be careful with humors.

32. When was the last time you…

33. Hello from the other side…

34. 🥳It’s Friday.

35. Coffee is for closers

36. TGIF

Subject lines with numbers

Numbers always look promising. So, don’t hesitate to use them in your cold email subject lines.

37. ⚡Grow your email list 20X.

38. Scale your business 10X.

39. Increase your website traffic 10X.

40. Take your business to the next level.

41. Boost your sales 10X.

Subject lines referring to others’ opinions

It is always a good idea to refer those whose opinions can be influential. These can be famous people, other customers, etc.

42. 700 thousand customers can’t be wrong.

43. {company name} boosted sales using {product/service name}.

44. {famous personality} has used {product/service name}recently.

45. 500 thousand customers trust {product/service name}.

Subject lines with straightforward offer

While crafting your email subject lines, try to be straightforward. Even one to-the-point offer or a question can significantly increase your open rates.

46. Email automation tools you shouldn’t miss out on.

47. New web scraping tool to boost your business growth.

48. A new tool to amplify your financial services.

49. SEO tool to help you boost traffic.

50. New meeting tool to let you host over 20 participants.

Final thoughts

It is not easy to write attractive and exceptional subject lines for cold emails. Prospects respond differently to different subject lines. The good news is that you can use segmentation and personalization for your email subject lines, and perform A/B tests to significantly increase the open rate of your emails.

Before sending out your emails, make sure that your subject line is honest, informative, and helpful to your prospects, and that it clearly states the value you want to offer your audience.

Crafting the best subject lines for cold emails can be a challenge, but it pays off in the end.

Personalize emails, automate inbound follow-ups, and grow your sales by nurturing relationships in one centralized platform.

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