Sending cold emails to prospects is an essential part of modern business communication. But with a deluge of emails flooding inboxes daily, creating a subject line that stands out and entices the recipient to open the email is critical. 

The subject line is the first thing the recipient sees, and it's the deciding factor in whether the email gets opened or sent straight to the trash folder. Therefore, crafting compelling cold email subject lines is an art every marketer or salesperson should master.

In this blog post, we'll delve into the best practices for writing subject lines that grab attention and boost the open rates of your cold emails.

What are cold emails?

Cold emails are unsolicited emails sent to potential customers or clients who have yet to express any prior interest in a product or service. These emails are a part of outbound marketing strategies used to generate leads and initiate sales conversations. 

Cold emails can effectively reach many people and generate interest in a product or service, but they can also be perceived as spam if not done correctly. To be successful, cold emails need to be personalized, relevant, and provide value to the recipient. 

The subject line is a recipient's first impression of the email, which can make or break the chances of the email being opened and read. Therefore, crafting an attention-grabbing cold email subject line is crucial to the success of any campaign. 

Why are cold email subject lines important?

Subject lines are crucial in cold emails because they are the first thing the recipient sees in their inbox. They determine whether the email will be opened or ignored and can ultimately determine the success or failure of the email campaign. 

33% of email recipients open an email based on its subject line. A good subject line should be attention-grabbing, clear, and relevant to the recipient.

For example, consider the following two cold email subject lines:

"Marketing Services for Your Business"

“How Your Business Can Generate 3x More Leads in 30 Days.”

  • The first subject line needs to be more specific and give the recipient a clear idea of what the email is about. 
  • The second subject line is specific and benefits the recipient's business. It's more likely to catch their attention and entice them to open the email.

In addition to catching the recipient's attention, subject lines also set the tone for the email. For example, a cold email subject line that is too aggressive or pushy may turn off the recipient, while a subject line that needs to be more specific may inspire confidence in the sender. Overall, subject lines are a critical component of successful cold email campaigns.

Characteristics of effective cold email subject lines

Crafting a compelling cold email subject line can be challenging, but specific characteristics can help make your subject line stand out and increase the chances of your email being opened. Here are some characteristics of effective subject lines:

1. Clear and concise

A clear and concise subject line is crucial for grabbing the recipient's attention. A subject line that is too long or complicated may get overlooked, so keep it short and simple.

2. Personalized

Personalizing the cold email subject line with the recipient's name or other relevant information can make your email stand out, so consider including the recipient's name or referencing a recent event or project they were involved in. This shows that you've researched and are genuinely interested in connecting with them.

3. Specific and relevant

Ensure your subject line is specific and relevant to the recipient's needs or interests. Avoid using vague or generic subject lines that could apply to anyone.

4. Urgency

Creating a sense of urgency in your cold email subject line can encourage the recipient to open your email immediately. Using time-sensitive words like "limited time" or "urgent" can help create a sense of urgency.

5. Intrigue

An intriguing subject line can pique the recipient's curiosity and make them want to know more. A question or a statement that sparks their interest can help accomplish this.

6. Non-spammy

Avoid using spammy language or excessive punctuation, as this can make your email look unprofessional and may even trigger spam filters. Instead, focus on using clear and straightforward language that accurately represents the content of your email.

A compelling cold email subject line should be attention-grabbing, personalized, specific, and relevant to the recipient's needs. By incorporating these characteristics, you can increase the likelihood of your cold email being opened and read by the recipient. 

Best practices for writing cold email subject lines

1. Do your research

Before writing your cold email subject line, it's essential to do your research on your target audience and what would interest them. This could involve looking at their website, social media accounts, or past emails to understand their tone and preferences. 

By researching, you can tailor your subject line to your audience's specific needs and interests, increasing the chances of them opening and engaging with your email. Research shows that personalized emails have a 50% greater chance of being opened. 

2. Experiment with different types of subject lines

To increase the chances of getting a response from your cold email, it's essential to experiment with different types of subject lines. This means trying different approaches, such as personalized subject lines, questions, teasing statements, or emojis. By experimenting with different styles, you can determine what works best for your target audience.

It's important to remember that what works for one audience might not work for another, so keep an open mind and be willing to try new things to find what works best for your target audience. Here's a mix of things you can try:

Benefit-focused cold email subject lines

These are a great way to grab your recipients' attention by highlighting the value or benefit they can receive from reading your email. These subject lines focus on the specific benefits your product or service can provide the recipient rather than just describing what the email is about.

For instance, instead of a subject line like "New Product Launch," you could try a benefit-focused subject line like "Discover the Secret to Boosting Your Sales with Our New Product." This subject line tells the recipient what the email is about and highlights the benefit they will receive by reading it.

Curiosity-inducing cold email subject lines

These are another effective way to grab the recipient's attention and make them want to open your email. These subject lines create a sense of mystery or intrigue, leaving the reader curious about what's inside the email.

For example, a subject line like "I can't believe what I just found out!" would naturally pique someone's curiosity and make them want to learn more. Another example could be "You won't believe what we have in store for you," which creates a sense of anticipation and excitement.

Social proof cold email subject lines

Social proofs are a great way to showcase your authority and credibility to your audience. This type of subject line uses social proof, such as a well-known client or many satisfied customers, to make your email more appealing to the recipient.

For example, "Join [Well-Known Company] and [High Number] Other Satisfied Customers!" is a great social proof subject line that can pique the interest of potential customers. Another example could be "See What [Well-Known Person] Has to Say About Our Services." 

3. Use A/B testing to determine effectiveness.

A/B testing is a powerful tool that can help you determine the effectiveness of your cold email subject lines. By comparing the performance of different subject lines, you can identify which ones are most likely to get your emails opened and read. 

To conduct an A/B test, send two versions of your email to a small sample of your email list with different subject lines. After tracking the open and click-through rates, you can determine which subject line performed better and use it for the remaining recipients. Remember that A/B testing should be ongoing, as what works for one campaign may not work for another.

Define your hypothesis

When it comes to A/B testing, the first step is to define your hypothesis. This involves deciding what you want to test and what you hope to achieve. For example, suppose you're testing subject lines for your cold email campaign. Your hypothesis might be that personalized subject lines will result in a higher open rate than generic subject lines.

Defining your hypothesis will help you focus your testing efforts and ensure you're measuring the right metrics. It's essential to keep in mind that you should only test one variable at a time to get accurate results. In the case of subject lines, this means testing only one type of subject line at a time.

Once you've defined your hypothesis, you can move on to the next step of A/B testing: creating your test groups.

Create test groups and variables.

Once you have your hypothesis, the next step is to create test groups and variables. Test groups refer to the groups of recipients who will receive different subject lines, while variables refer to the specific elements that you will change in each subject line. 

For example, suppose you are testing the effectiveness of personalized subject lines. In that case, your test groups consist of two segments of your email list - one that receives a generic subject line and the other that receives a personalized subject line. 

In this case, the variable would be the specific personalized element you add to the subject line, such as the recipient's first name. By having clear and distinct groups with only one variable being changed, you can accurately attribute any changes in open rates or engagement to the tested variable.

Analyze results and make adjustments.

If one subject line outperformed the other, consider why. Was it because of the wording or the tone of the subject line? Was it because of the use of personalization or social proof? Use this information to adjust your future subject lines and continue testing to optimize your results.

For example, you ran an A/B test with two subject lines: "Get 50% off your next purchase" and "Exclusive deal for our valued customers." The first subject line had an open rate of 20% and a response rate of 5%, while the second subject line had an open rate of 30% and a response rate of 7%. 

Based on these results, the second subject line was more effective because it had a higher open rate and response rate. You might also hypothesize that using the word "exclusive" and the phrase "valued customers" resonated better with your audience and adjust future subject lines accordingly.

Examples of effective cold email subject lines 

Personalized cold email subject lines

Here are a couple of examples of effective personalized subject lines that show that you care enough to make an effort:

1. [First Name], can we discuss [relevant topic]?

This subject line shows that you've done your research and are reaching out to the recipient about a topic that's relevant to them. 

For example, "Sarah, let's chat about your recent blog post on social media strategy." This approach will likely catch the recipient's attention and encourage them to open the email.

2. Quick question about [company/industry]

This subject line shows that you're interested in the recipient's company or industry and have a specific question for them. 

For example, "Quick question about your recent product launch, [Recipient Name]." This approach can pique the recipient's interest and encourage them to open the email to learn more.

Benefit-focused cold email subject lines

Here are a couple of examples of effective benefit-focused subject lines that highlight the value your product or service can deliver to your recipient:

3. Improve [specific metric] with [your product/service]

This subject line shows that your product or service can help the recipient achieve a specific goal or improve a particular metric. 

For example, "Improve your email open rates with our new subject line analyzer." This approach can be particularly effective if you know that the recipient is struggling with a specific issue.

4. [Recipient's Company] could be saving thousands with [your product/service]

This subject line highlights the potential cost savings your product or service can provide to the recipient's company. 

For example, "Acme Corp could save thousands with our energy-efficient lighting solutions." This approach can be particularly effective if you're reaching out to a decision-maker in a company.

Curiosity-inducing cold email subject lines

Here are a couple of examples of effective curiosity-inducing subject lines that can pique the recipient's interest and encourage them to open the email to learn more:

5. Is this [specific challenge] keeping you up at night?

This subject line shows that you understand the recipient's pain points and have a potential solution for them. 

For example, "The shortage of qualified candidates keeping you up at night?" This approach can be particularly effective if you're contacting a decision-maker in HR.

6. [Mutual Connection] recommended I reach out to you

This subject line highlights a mutual connection between you and the recipient and can help establish trust. 

For example, "Jane Smith thought you might be interested in our new product launch." This approach can be particularly effective if a mutual connection with a strong relationship with the recipient has been referred to you.

Social proof cold email subject lines

Here are a couple of examples of effective social proof subject lines that can help you establish trust and credibility:

7. [Your Company] is trusted by [list of reputable clients]

This subject line shows that your company has worked with other reputable companies and has a proven track record of success. 

For example, "Why XYZ Company is trusted by Fortune 500 companies like Microsoft, Amazon, and Google." This approach can be particularly effective if you're contacting a decision-maker in a large organization.

8. [Industry Leader] recommends [your product/service]

This subject line highlights the endorsement of a respected industry leader and can help establish credibility for your product or service. 

For example, "Marketing guru Neil Patel recommends our new SEO tool." This approach can be particularly effective if you're reaching out to a decision-maker in a company with multiple options at its disposal.

P.S. Are you sure you use the right software for your cold email outreach? Here's a guide to help you decide. 

 Let's revise. Here are five more cold email subject lines. Can you see why they work?

9. “Quick question about [company name]”

This subject line works because it's short to the point and implies that the email will only take up a little of the recipient's time. Using the recipient's company name also shows that the sender has done their research and is targeting them specifically.

10. “5 ways to boost [specific metric] in [industry/niche].”

This subject line works because it's specific and offers value to the recipient. It promises to share actionable tips that can help improve a specific metric, and by referencing the recipient's industry or niche, it shows that the sender understands their specific needs.

11. "Your competitors are using [product/service], are you?"

This subject line works because it creates a sense of urgency and plays on the recipient's fear of falling behind their competitors. It's also an excellent way to introduce a product or service, as it immediately frames it as being used by successful competitors.

12. "Idea for your next blog post: [specific topic]."

This subject line works because it's personalized and shows that the sender has taken the time to understand the recipient's content needs. Offering a specific idea for a blog post also shows that the sender is knowledgeable and can offer valuable insights.

13. "How [specific company] improved [specific metric] by [specific percentage]."

This subject line works because it offers a concrete example of success and shows that the sender has done their research. Including a specific company and metric also shows that the email is tailored to the recipient's specific industry or niche.

Businesses can improve email open rates and drive more sales by understanding the target audience and crafting cold email subject lines that meet their needs.

Some extra cold email subject line tips

1. Keep an eye on your competitors' subject lines

One of the best ways to gain a competitive advantage is by studying the subject lines of your competitors' cold emails. Take note of what works and what doesn't work for them. Look for patterns and themes that resonate with their audience. You can use this information to create subject lines that are even more compelling.

For example, let's say you're in the software industry, and you notice that one of your competitors consistently uses subject lines that focus on the cost-saving benefits of their product. You can take note of this and incorporate it into your subject lines, but with a unique spin that sets you apart from your competition.

2. Use data and insights to inform your subject lines

Data and insights can be a powerful tool for crafting compelling subject lines for cold emails. Look at past email campaigns and analyze which subject lines received the most opens and click-throughs. Use this information to inform your future subject lines.

For instance, if you notice that subject lines with numbers and statistics perform well with your audience, you can use this knowledge to create subject lines that highlight crucial metrics or data points that demonstrate the value of your product or service.

3. Be bold and try something new

Experimentation and creativity can help you stand out and gain a competitive advantage in cold emails. Be bold, try new approaches, and take risks with your subject lines.

For example, try using humor in your subject lines to grab the reader's attention and make them more likely to open your email. Alternatively, you could use a provocative or controversial subject line to pique the reader's interest and encourage them to engage with your message.

P.S. Here are some killer subject line examples for your follow-up emails.

Common cold email subject line mistakes to avoid

A few common mistakes should be avoided when crafting cold email subject lines to ensure your email stands out and gets opened. Here are some of the most common mistakes to avoid:

1. Being too vague or generic

An overly generic or vague subject line may not give the recipient a clear idea of what the email is about, which can lead to it being ignored or deleted. Avoid using subject lines like "Hi there" or "Quick question" and instead be specific about the email.

2. Using spammy language

Using words or phrases commonly associated with spam can cause your email to be filtered directly into the recipient's spam folder. Avoid using words like "free," "limited time offer," or "act now" in your subject lines.

3. Being too salesy

While the ultimate goal of a cold email may be to make a sale, being too pushy or aggressive in the subject line can turn off potential customers. Avoid using subject lines that sound like a sales pitch, such as "Buy now and save!" Instead, focus on providing value or solving a problem for the recipient.

4. Making spelling or grammar mistakes

A subject line with spelling or grammar mistakes can make your email appear unprofessional and untrustworthy. Always double-check your subject lines before sending them to ensure they are error-free.

5. Not personalizing the subject line

Personalization is critical in cold email outreach, and failing to personalize the subject line can make the email seem generic and impersonal. Use the recipient's name or company in the subject line to clarify that the email is tailored to them.

Elevate your outreach with effective subject lines 

Subject lines are just the beginning of a successful cold email campaign but can significantly affect the overall outcome. So remember to apply these tips and best practices in your cold email outreach efforts.

By doing so, you can improve the chances of your prospects opening and reading your emails. With persistence and experimentation, you can discover the best subject lines for your audience and help you achieve excellent results.

Suppose you're seeking a reliable way to generate compelling subject lines and streamline your cold email campaign; consider leveraging Outplay's AI writer. 

Our AI writer is designed to assist you in creating subject lines that are tailored to your audience, ensuring higher open rates and improved outcomes. With the AI's ability to analyze data and trends, it can suggest subject lines that are both effective and engaging, ultimately helping you achieve exceptional results in your cold email outreach endeavors.