The Art and Science of Crafting Best Cold Email Subject Lines

Countless emails flood our inboxes every day, capturing the attention of recipients has become a formidable challenge. For those seeking to forge new connections and explore opportunities, cold emailing has emerged as a valuable tool.

However, amidst the sea of unread messages, how can one ensure that their email stands out and entices the recipient to open it? The answer lies in the art of crafting irresistible subject lines that engage, pique curiosity, and compel readers to delve further into the email’s content.

In this article, we will delve into the fascinating realm of subject line creation for cold emails, uncovering the secrets behind crafting subject lines that not only evade the clichéd corporate language but also resonate with recipients on a human level.

Gone are the days of stiff and impersonal messages that fail to make an impact. Instead, we’ll explore techniques that breathe life into your subject lines, allowing them to shine amidst the monotony of traditional approaches.

From evoking emotions to offering personalized value, we’ll explore a range of strategies that leverage the power of human connection. The goal is to transform your subject lines into captivating invitations, drawing readers into a dialogue that promises mutual benefit.

With practical tips and examples, we’ll empower you to infuse your cold emails with a touch of authenticity and relatability that will leave a lasting impression.

Throughout this journey, we’ll navigate the fine balance between professionalism and approachability, acknowledging that behind every email address is a real person with interests, motivations, and unique perspectives.

By embracing this understanding, you can revolutionize your cold emailing game and unlock a wealth of opportunities for meaningful connections, fruitful collaborations, and business growth.

So, let’s embark on this captivating exploration of the art of crafting the best subject lines for cold emails, where the human touch reigns supreme, and every other subject line works and has the potential to spark curiosity and forge lasting connections.


The Importance of Cold Email Subject Lines

When it comes to cold email outreach, the role of subject lines cannot be overstated. The subject line plays the critical first impression, and in many cases, it’s the deciding factor between your email being opened or relegated to the depths of your prospect’s inbox.

Making Your Subject Line Stand Out

Your cold email subject line should stand out like a lighthouse in the crowded sea of your prospect’s inbox. Keep the subject line short yet powerful; shorter subject lines work better on mobile devices and don’t get cut off by email providers.

Using personalized subject lines can make a significant difference. Include the company name or reference a mutual connection, the same event, or even the same conference you both attended.

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Consider this: “John from XYZ Corp suggested we connect” versus “Can we chat?”. The former is far more likely to attract the attention of your recipient. The personal touch instantly gives your cold email credibility and relevance.

Power Words in Subject Lines

Power words are a golden ticket to making your cold email subject lines more persuasive. They are words that trigger an emotional or psychological response, causing the reader to feel intrigued, excited, or curious.

For instance, ‘exclusive,’ ‘limited,’ ‘breakthrough,’ ‘innovative,’ ‘insider,’ are all power words that catch your audience’s interest. Incorporating these into your subject lines effectively will make them hard to resist.

Avoiding the Spam Folder

As much as we strive to create catchy subject lines, it’s crucial to be mindful of spam filters. Generic, subject line triggers, lines, clickbait subject lines, or subject lines that create a false sense of urgency can trigger spam filters, causing your emails to land straight into the spam folder.

Follow these few cold email tips: Avoid excessive use of caps lock, exclamation points, and words like ‘free,’ ‘buy now,’ ‘guarantee,’ that are common spam triggers.

Aligning the Subject Line with the Email Body

A good email subject line isn’t just catchy—it aligns with the email body. The last thing you want is for your recipient to feel duped.

Misleading your email recipients may increase open rates momentarily, but it’ll hurt your reputation and response rates in the long run.

Addressing the Prospect’s Pain Point

One of the best ways to grab your prospect’s attention is by addressing a common pain point in your subject line. Showing an understanding of your prospect’s pain point right off the bat can be highly effective.

For instance, if you’re reaching out to a tech startup, a subject line like “Reduce your app’s churn rate” is bound to pique interest.

In this first part, we’ve explored the importance of cold email subject lines, how to make them stand out, the role of power words, how to avoid spam filters, and the effectiveness of addressing pain points.

Examples and Principles of Good Subject Lines

Crafting the First Subject Line

The first subject line of your cold email is the equivalent of a first impression. It needs to be a good subject line, and it should immediately grab the reader’s interest. Here are a few examples of good subject lines:

  • “Save 15% on your monthly software subscription”
  • “How to increase your blog post engagement by 50%”

These examples offer clear value propositions and are likely to resonate with your target audience.

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For cold email examples, we made a separate article about that that you can check out.

Short vs. Long Subject Lines

The debate over short subject lines versus longer, more detailed ones is ongoing. Short subject lines are often viewed as more impactful.

They’re concise, to the point, and ideal for mobile users. For instance, “Boost Sales Now” is short yet impactful.

On the other hand, longer subject lines provide more context, which can be helpful in specific scenarios.

If you’re offering a unique, complex solution, a longer subject line like “Discover our AI-powered sales optimization tool for e-commerce” may be more fitting.

It’s a balancing act between keeping the subject line short and providing enough information to spark interest.

Testing Different Subject Lines

When it comes to email subject lines, one size doesn’t fit all. It’s essential to test different subject lines to see what works best for your specific audience.

Use A/B testing for different variations of your subject line, with variations in length, tone, use of power words, or personalization.

Best Subject Lines for Follow Up Emails

Follow-up emails require their own set of best subject lines. Here are a couple of email: best subject line examples for follow-up:

  • “Meeting recap and next steps”
  • “Did you get a chance to review our proposal?”

In these examples, the subject lines are short, to the point, and immediately provide context for the email content.

Subject Lines Triggering Curiosity

Creating a sense of curiosity in potential customers can work wonders for your cold email subject line. Subject lines like “Discover the secret to boosting conversion rates” or “Unleash untapped potential with our new SEO tool” make your prospects curious about what you’re offering.

Subject Line and the Reader’s Interest

While crafting your subject line, consider your reader’s interest. Your subject line should connect with what they care about—their goals, challenges, and the industry they’re in.

Keep your target audience in mind when writing subject lines to increase your chances of capturing their attention.

Best Cold Email Subject for Different Business Domains

Your cold email subject line and lines should change based on the business domain. A software company’s pain point differs from that of a marketing agency or a finance firm.

In the following sections, we’ll guide you through how to craft effective cold email subject lines for different business sectors.

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Remember, to boost your cold email campaign efforts, sign up for Mailarrow, our cold email outreach software.

With Mailarrow, you can efficiently manage your cold emails, follow-ups, and track the results.

Crafting Cold Email Subject Lines for the Software Industry

The software industry often grapples with challenges related to product development, feature utilization, user experience, and customer retention.

A powerful subject line for this sector would address a few words these pain points. For instance:

  • “Streamline Your Development Process with Agile Tools”
  • Boost Your SaaS Product’s User Engagement

These subject lines touch upon the common pain points in the software industry and suggest a solution, making them attractive to open.

Effective Cold Email Subject Lines for the Marketing Sector

In the marketing sector, the primary pain points revolve around lead generation, customer engagement, brand awareness, and return on marketing investment. Hence, subject lines like:

  • Double Your Lead Generation with Proven SEO Strategies
  • “Amplify Your Brand Awareness with Influencer Partnerships”

They directly target the pain points and propose a benefit, which makes them compelling for marketing and business professionals too.

Cold Email Subject Lines for the Finance Sector

Finance professionals are concerned about regulatory compliance, risk management, investment strategies, and financial efficiency.

Thus, personalized subject lines for blog post in this sector could be:

  • “Achieve Regulatory Compliance with Our Risk Assessment Tool”
  • “Maximize Your ROI with Our Investment Insights”

These subject lines communicate understanding of the recipient’s challenges and suggest a possible solution, making them more likely to be opened.

Subject Lines for Other Sectors

The same principle applies to other sectors. Understand their unique challenges and tailor your subject lines to address those pain points.

For example, in the HR sector, a subject line like “Reduce Your Hiring Time by 40%” would be quite appealing.

Maintaining Relevance with New Subject Lines

As industries evolve, so should your cold email subject lines. Keeping up with industry trends, news, and changes will allow you to craft subject lines that are timely and relevant.

This is an ongoing process that can significantly boost your email open rates over time.

Remember, the right cold email subject line can make a significant difference in your outreach efforts.

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To streamline this process, consider using Mailarrow, our cold email outreach software.

With our tool, you can effectively manage your email outreach and continually optimize your subject lines for better performance.

Importance of Personalization in Subject Lines

Personalized subject lines can significantly boost your email open rates. A study by Experian found that personalized subject lines deliver 26% higher unique open rates overall.

They make the recipient feel acknowledged as an individual rather than being just another name on a generic email list.

Using Company Names in Subject Lines

Including the company name in the subject line is one way to personalize cold emails. It shows that you’ve taken the time to research about the company.

For instance, if the prospect’s company is “TechForward,” your subject line could be:

  • “TechForward – Boost Your Sales with AI Solutions”
  • “How TechForward Can Benefit from Cloud-Based Accounting”

By doing so, you’re not only adding a personal touch, but also highlighting the relevance of your email to the prospect’s business.

Leveraging Mutual Connections in Subject Lines

Another effective way to personalize your cold email subject lines is to leverage mutual connections, if you have any.

This not only grabs the prospect’s attention but also lends credibility to your email. Here’s how to incorporate this:

  • “John Smith recommended I reach out to you”
  • “Met you at the same conference as Jane Doe”

Personalized Subject Lines Using Roles or Achievements

Another powerful way to personalize your sales email subject lines is to acknowledge the prospect’s role or recent achievements. For example:

  • “Congrats on your promotion, {FirstName}”
  • “{FirstName}, how does ABC Corp deal with its growing user base?”

Dynamic Content in Personalized Subject Lines

Personalized subject lines can go beyond just using the recipient’s name or company. Dynamic content like location, time, events, or user behavior can be used to craft creative subject lines that appeal to the recipient. For example:

  • “{FirstName}, we’ve got an exclusive offer for our New York customers!”
  • “{FirstName}, your yearly subscription ends in 5 days. Let’s renew!”

Remember, personalization is about relevance. Your subject lines should resonate with the recipient’s interests, needs, or pain points to be effective.

To craft compelling personalized subject lines and manage your cold email outreach seamlessly, consider using Mailarrow.

It’s a robust cold email outreach software designed to help you boost your email open and response rates.

In the following sections, we will delve into more strategies for crafting effective cold email subject lines.

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Understanding Spam Filters

Email providers have spam filters in place to protect users from unwanted emails. These filters look at various aspects of your email, including the subject line.

To ensure your cold emails land in the prospect’s inbox, you need to avoid spam-triggering words in your subject line like “free,” “guarantee,” “no obligation,” and excessive use of symbols or capital letters.

Importance of Subject Line Length

The length of your subject line plays a significant role in email deliverability. Most email providers display about 60 characters of the subject line, and mobile devices usually show just 25-30 characters.

Hence, shorter subject lines are often more effective, especially considering the increasing number of people checking emails on mobile devices.

Creating a Sense of Urgency

Creating a sense of urgency in your subject line can prompt your email recipients to open your email. However, it needs to be done sparingly and genuinely.

Phrases like “limited time offer” or “ends today” can make your subject line stand out in a crowded inbox.

Subject Line and the Email Body Consistency

The email subject line and the email body need to be consistent. Misleading or clickbait subject lines may increase your open rates temporarily, but they can also annoy recipients and hurt your reputation in the long run. Make sure your subject line accurately reflects the content of your email.

Using Power Words

Power words in your subject line can trigger an emotional response and make it stand out in a prospect’s inbox. Words like “discover,” “exclusive,” “boost,” and “unlock” can make your subject line more compelling.

Encouraging Social Proof

Incorporating social proof in your subject line can also increase your email open rates. For instance, “Join 5,000+ businesses boosting their sales with our tool” can add credibility and spark curiosity.

Remember, every email and audience is unique. You should continuously test and tweak your subject lines to find out what works best for your specific audience.

To manage this effectively, consider using Mailarrow, our cold email outreach software. It allows you to run A/B tests, track open and response rates, and optimize your outreach campaigns.

The Importance of A/B Testing Subject Lines

A/B testing involves sending two different subject lines to small segments of your email list, then analyzing which one had a better open rate.

By constantly testing different subject lines, you can learn more about what catches your target audience’s interest.

For example, you might test the effectiveness of a short subject line against a longer one, or a subject line with a company name versus one without.

A/B testing is all about exploring these different approaches and finding what works best for your audience.

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Testing Multiple Subject Lines

A good A/B test should only have one variable. If you’re testing the length of your subject lines, make sure that’s the only difference between the two.

If you change multiple elements at once (such as length and tone), you won’t know which change led to a difference in response rates.

Learning from Top Performing Subject Lines

Always keep a record of your top performing subject lines. This will help you identify patterns or strategies that resonate with your audience.

It could be a specific power word, a certain length, or the use of a sense of urgency. Use this knowledge to refine your future emails and subject lines and boost your cold email campaign success.

Iterating on Subject Lines for Follow Up Emails

Don’t just iterate on your first subject line; follow-up emails are equally important.

You could even reference your previous email in your follow-up subject line, for example: “Re: Our proposal for boosting TechForward’s sales” or “Following up on our cloud-based accounting solution for TechForward.”

Implementing Feedback from Email Recipients

If a recipient replies to your cold email with feedback on your subject line, take it into consideration.

Whether it’s positive or negative, this direct input from your target audience is invaluable for refining your approach.

Creating, testing, and iterating on subject lines can be a challenging task, but with Mailarrow, our cold email outreach software, you can streamline this process and improve your open rates.

Understanding Your Audience’s Pain Points

One of the most effective ways to get your emails read is to address your prospect’s pain point in the subject line.

Identify the challenges your target audience faces and present your solution right in the subject line.

For example: “Boost Your SEO Rankings in Just 30 Days” or “Cut Your Payroll Processing Time in Half”.

Utilizing Social Proof

Social proof can serve as a powerful persuader. People often rely on others’ opinions and experiences to guide their decisions.

Leverage this by incorporating social proof in your subject lines. For instance: “Join 1000+ businesses optimizing their SEO with our tool”.

Keeping it Short and Sweet

Given that a significant portion of emails are read on mobile devices, it’s crucial to keep your subject lines short and to the point.

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Shorter subject lines tend to perform better as they’re more digestible at a glance.

Creating a Sense of Curiosity

Craft subject lines that pique the reader’s interest and encourage them to find out more. This can be as simple as asking a question or making a surprising statement. For example: “Do You Know What’s Holding Back Your SEO?”

Incorporating Personalization

Personalized subject lines stand out in crowded inboxes. Use the recipient’s name, reference their company, or mention a mutual connection to grab their attention.

Adding a Touch of Urgency

Creating a sense of urgency can motivate the recipient to act quickly. Use phrases like “limited time offer” or “ends soon” to further create a sense of urgency.

Avoiding Spam Filters

Avoid using words that trigger spam filters, like “free,” “guarantee,” or “no obligation.” Also, avoid excessive use of capital letters and symbols, which can land your email in the spam folder.

To conclude, crafting compelling subject lines for cold emails is both an art and a science. It requires understanding your audience, being creative, and continuously testing and improving.

By applying these strategies and best practices, you can increase your email open rates, drive engagement, and ultimately, gain more paying customers.

Start crafting effective cold email subject lines with Mailarrow, our cold email outreach software.

It offers a range of features, from personalized email automation to A/B testing, helping you improve your cold email outreach. Sign up for Mailarrow today!


Which are examples of good email subject line?

Good email subject lines are concise, compelling, and relevant to the content of the email. Here are a few examples:

  1. “Increase Your Sales by 20% in 30 Days”
  2. “Exclusive SEO Tips for [Company Name]”
  3. “Join 500+ businesses optimizing their SEO with our tool”
  4. “Limited Offer: Get 50% Off Our Premium Plan”
  5. “[Recipient’s Name], let’s boost your conversion rates!”

Remember, the best email subject lines will vary based on your specific audience and the nature of your email content.

What should be the subject line of a cold email?

The subject line of a cold email should be engaging, personalized, and provide a clear value proposition. Here are a few examples:

  1. “Saving [Company Name] 10 hours each week on payroll”
  2. “How [Your Company Name] can improve your marketing ROI”
  3. “Invitation: Exclusive Webinar for Business Growth”
  4. “[Recipient’s Name], increase your website traffic with us”
  5. “[Mutual Connection’s Name] recommended I get in touch”

These subject lines show the recipient why they should care about your email and encourage them to open it.

What should my email subject line be?

Your email subject line should be relevant to your email content and clearly indicate what the recipient can expect to find in the email.

It should be engaging, personalized when possible, and create a sense of urgency or curiosity. Keep in mind, the best email subject lines are often the result of testing different approaches and refining based on the results.

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With Mailarrow, our cold email outreach software, you can easily test and optimize your email subject lines to improve your open and response rates. Sign up for Mailarrow today!

Serge Shlykov is the founder of Mailarrow. Rotterdam Business School graduate and a long-time software engineer he has been running his own agency and SaaS business before realizing how many people are struggling with cold email outreach. This made him create Mailarrow, the cold email outreach software that helps you build great relationships at scale. Find him on Twitter and LinkedIn

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