30 Catchy Subject Lines to Elevate Your B2B Cold Outreach

Did you know that the average open rate for sales emails is just 23.9%?

Low open rates can result in many issues with your cold emailing campaigns, such as low engagement, wasted resources, and a lot of missed opportunities.

And the key to overcoming this challenge is straightforward: 

You must craft more catchy subject lines for your cold emails.

The subject line is the first element of your email that prospects will see. Thus, making it captivating can turn many of your overlooked emails into compelling sales messages that drive action.

In this guide, we’ll explore the art of writing irresistible cold email subject lines, helping you skyrocket your open rates and engagement. We’ll cover best practices, pitfalls to avoid, and provide a wealth of high-converting subject lines to power up your next B2B campaign.

Ready to transform your unread emails into real sales opportunities? Let’s dive in!

What is a Cold Email Subject Line?

In cold emailing, the subject line functions similarly to a headline in a news article or a title of a book. It’s the element of your email that appears next to your name in the prospect’s inbox.

Subject lines are the first glimpse a recipient gets of what the email contains. Thus, they should be designed to captivate attention and entice the reader to delve deeper. 

The maximum length of a subject line in an email differs from one email provider to another. What’s most important to note is that:

  • For desktop devices: your subject lines will only display around 60-70 characters.
  • For mobile devices: the character count is even more reduced, with many showing only 25-30 characters of a subject line.

What Makes Subject Lines an Important Element in Cold Emailing?

In the vast worlds of sales outreach and cold emailing, subject lines play a pivotal role in a company’s success. This is simply because they are often the deciding factor on whether your email gets opened and read or is totally ignored.

Here’s a quick stat for you:

47% of email recipients open an email based on the subject line alone.

If that number should tell you one thing, it’s that subject lines can make or break your cold outreach efforts. Email marketers know that a poorly crafted subject line will prevent any meticulously written email from seeing the light of day.

A great subject line for cold emails will:

Cold Email Subject Line

Open the Door to Flawless Communication

The subject line sets the stage for what to expect and what’s to come next. If it resonates with the reader, it will spark curiosity and encourage them to open the email. This opens the door to further communication, allowing you to build a solid, trust-based connection right off the bat.

Enhance Your Brand’s Image

Your subject line is more than just a prompt for your prospects to open an email. It’s a representation of your brand and what you stand for. A well-crafted, professional subject line gives recipients a positive initial impression of your company’s communication style and professionalism. Conversely, a misleading subject line, for example, can negatively impact any brand’s image and cause a great deal of mistrust.

Maximize Engagement Rates

The role of a subject line doesn’t end with getting the email opened. It actually initiates a chain reaction, extending its influence to contribute to the overall success of your campaign. By setting the right tone and expectation, compelling subject lines will also boost click-through rates and responses.

What Makes a Good Cold Email Subject Line?

Crafting compelling cold email subject lines is a delicate balancing act. They must spark curiosity and establish relevance, all within just a few carefully chosen words. They should also be easily personalizable to capture more attention and foster a sense of connection, while being direct enough to clearly convey your intent.

Here are four tips to help you create high-converting B2B cold emailing subject lines:

Be Brief and Direct

The best cold email subject lines get straight to the point. They clearly state the email’s purpose, thus respecting the recipient’s time. Vague or misleading subject lines may, in fact, lead to high initial open rates. However, prospective buyers will make sure not to reply and will likely ignore your outreach attempts in the future.

How can you be direct in your email subject lines?

Use them to provide an accurate reflection of the content of your email. For example, if you’re reaching out to talk about a product demo, mention that in the subject line. A straightforward subject line that sets the right expectations will earn respect and increase the chances of your email being read.

Enhance Curiosity and Urgency

Curiosity is a powerful driver of human behavior. And creating a sense of urgency is what often makes us click on a news article, watch a movie, or, in this case, open an email.


Provoking curiosity and urgency in a 30-character cold email subject line is an art where balance is key. You have to reveal enough to make the email’s value clear, yet withhold enough to entice the reader to click, read more, and respond.

An effective way to enhance curiosity is by asking a question. For instance, instead of stating, “Implement Our New Software Solution,” a more curiosity-inducing subject line tailored to the B2B software tech sector could be, “Want a Smarter Workflow with Our AI Solution?”

Optimize For Mobile Devices

According to a study by Litmus in 2021, 41.6% of email opens occur on mobile devices. With such a significant percentage of emails being viewed on smaller screens, it’s crucial to optimize your subject lines for mobile viewing, particularly in terms of length.

On most mobile devices, and with most email providers, email subject lines get cut off after 50-60 characters. So, if your subject line is too long, your message might be ignored and buried within the inbox.

To avoid this, it’s vital to keep your subject lines concise and ensure that the most critical information is at the beginning. Additionally, you might want to consider how your subject line will appear in push notifications. A well-optimized subject line can catch a recipient’s attention even when they’re not actively checking their inbox.

Avoid Spam Triggers

Spam filters are becoming increasingly sophisticated. There are many terms and punctuation in your subject line that can trigger them. For instance, words like ‘free’, ‘buy now’, ‘urgent’, ‘winner’, and ‘cash’ may make your email appear spammy, causing it to land in the junk folder.

In addition:

Using all caps, excessive punctuation (especially exclamation marks), or including numbers and symbols where they aren’t necessary can raise flags for spam filters.

To ensure your cold emails reach the intended inbox, use a natural conversational tone in your subject lines. Feeling stuck? Try using ChatGPT and a rewording tool to generate subject lines. ChatGPT can help you brainstorm unique ideas, and a rewording tool can turn those robotic subject lines into more engaging and click-worthy ones.

Cold Email Subject Line

How Long Should Your Cold Emailing Subject Lines Be?

Most experienced email marketers understand that the perfect length for a subject line doesn’t necessarily exist. However, it’s good practice to keep your subject lines between 6 and 10 words (around 50 characters or less).

This ensures that your subject lines are fully displayed on most devices and email clients. It also plays a role in determining whether your email will be marked as spam. Email clients, such as Gmail, have spam filters that may flag overly long or short subject lines as spam.

30 Successful Cold Email Subject Lines to Skyrocket Your Open Rates

Now that we understand the principles behind effective cold email subject lines, let’s look at some practical examples. 

Of course, the examples we’ll provide here aren’t meant to be copied and pasted verbatim. Instead, they should be an inspiration or a guide for you to start your cold emailing journey.

Best subject lines for cold email networking to elevate your open rates:

Short, Yet Effective Cold Email Subject Lines:

  1. Three ideas to overcome {common pain point}
  2. Quick question about {target company name}
  3. Something for you
  4. Free today at {time of the day}?
  5. Can we chat about {relevant topic}
  6. {referral} recommended I reach out to you
  7. Let’s connect.
  8. Impressed by {recent company achievement}

Subject Lines for Personalizing Emails:

  1. Looking to outsource {challenging task}?
  2. {Your company name}’s answer to {common pain point}
  3. Cut down your {challenging task} costs by {tangible outcome}
  4. Struggling to improve your {desired result}?
  5. {product or service}: an innovative solution for {problem}
  6. A new way to boost {desired result} by {tangible outcome}
  7. Tailored {challenge/industry} solutions for {target company name}
  8. Is your team struggling with {common pain point}? We can help”

Subject Lines for Startups:

  1. Ready to disrupt the {industry name} space?
  2. How {your startup} can help {target company name} innovate
  3. Drive {desired outcome} with {your startup’s product/service}
  4. Let’s unleash your growth with {your startup}
  5. Transforming {industry name} one step at a time
  6. Reimagining {common industry process/task}
  7. Let’s partner for the future of {industry name}

Subject Lines for IT and Tech Companies:

  1. Streamlining {common tech task} for {target company name}
  2. {Your company name} – Bringing efficiency to your IT operations
  3. Harness the power of tech with {your company name}
  4. Resolving {common tech challenge} for good
  5. Empowering {company Name} with advanced {IT solutions}
  6. Your next step toward digital transformation
  7. Boost productivity with {specific technology}

How to Test and Optimize Cold Email Subject Lines?

Crafting effective subject lines for your cold emailing campaigns is an iterative process. It requires constant testing, analysis, and tweaking before you find the optimal subject line. One of the most efficient ways to accomplish this is through A/B testing.

A/B testing, also known as split testing, involves creating two different subject lines for the same email and sending them to two distinct subsets of your audience. Then, you’ll compare the performance of each subject line based on open rates and conversions.

Here are three crucial conditions for your A/B testing to be valid:

Test Only One Variable at a Time

It’s critical to keep your changes to a minimum so you can accurately attribute any performance differences to that specific change. All the other elements should be identical, especially the first line in your email content.

Ensure a Large Testing Sample 

To ensure the results of your A/B tests are statistically significant, you have to test your subject lines on hundreds of recipients. Basically, the larger your email list, the more accurate your testing will be. 

Conduct Tests Over Different Timings

Running a test for a short period doesn’t provide a comprehensive view of your subject line’s performance. For instance, it’s clear that sending emails during the weekend or busy work hours is a surefire way to have them ignored. This outcome isn’t related to the subject line used.

Therefore, to eliminate the time factor, ensure you send your emails at varying times throughout the day and week — and over an extended period.

How to Avoid the Spam Filter When Crafting Cold Email Subject Lines

One of the greatest challenges in email marketing is getting your emails past spam filters. Here are a few simple practices to improve your chances:

  • Avoid spam trigger words: These include terms and phrases such as “free,” “buy now,” “save,” “discount,” and “cash bonus.”
  • Don’t overuse capital letters or exclamation marks: Excessive use of these will make your email appear as spam.
  • Match your subject line with your email content: Misleading your prospects with inaccurate subject lines will always lead to high spam complaints. Ensure that your subject line accurately represents the content of your email.
  • Keep your subject line length in check: Very long subject lines can trigger spam filters. Aim to keep your subject lines between 5 to 10 words.

Wrap-Up: Best B2B Cold Email Subject Lines

Creating good subject lines for cold emails has always been a crucial skill in the B2B space. Your subject line will be the deciding factor on whether your cold emails are going to initiate a profitable business partnership or be ignored. 

With the insights, strategies, and examples shared in this guide, you’re now equipped to write subject lines that not only grab attention but also pave the way for successful business relationships.

Vito Vishnepolsky
Vito Vishnepolsky
CEO and Founder at Martal Group