Best Subject Line for Cold Emails That Get Results

Don't let your cold emails get lost in the inbox abyss. Discover the best subject lines that will grab attention and drive results with these tips from Unfiltered!
If you've been investing all your creative energy in crafting the perfect content for your cold emails but treating the subject line as a mere afterthought, you've discovered the reason behind your campaign's lackluster performance.

Think about it - how can you expect a response and lead nurturing if your recipients don't even open the email?

Your subject line is key to unlocking better open rates, click rates and call-to-action conversions. It's a big task for just 60 characters.

But worry not.

Once you discover the secret to composing the best subject line for cold emails, you'll create them easily and watch your open rates take flight.

In this article, we'll reveal the ingredients for a winning cold email subject line and share seven types of subject lines, along with examples, to help boost your open rates.

What Makes a Good Cold Email Subject Line?


The first thing you must do when writing a cold email subject line is to make sure it directly relates to the content of your message. A good subject line will highlight the value your recipient will gain by reading your email, enticing them to open and engage with your content.

Here are some tips for creating a relevant subject line:

  1. Be specific: Vague or broad subject lines won't grab the attention of your target audience. Instead, use specific details that showcase how your product or service can solve their problems or meet their needs.
  2. Use familiar terms or phrases: Incorporate terminology your prospects can easily recognize and relate to. This will make them more likely to open your email, as they'll feel it's relevant to their interests.
  3. Keep it short and sweet: Long subject lines are less likely to be read in full, especially on mobile devices. Aim for a subject line that's 60 characters or less to maximize readability and get straight to the point.
  4. Personalize it: Whenever possible, utilize personalization – such as the prospect’s name or other relevant information – to make the email feel made to them, increasing the chances they'll open and read it.

It's essential to continuously test different subject lines and analyze the results to improve your cold email open rates. Track metrics like open rates, click-through rates, and conversions to analyze the effectiveness of your subject line strategy.

Make adjustments to continuously optimize and refine your subject lines, maximizing the chances your audience will engage with your content.


Put yourself in your prospect’s shoes - they probably receive dozens of cold emails per day, and a complex subject line is the last thing they would open. So, your best bet is to get straight to the point and keep your subject line short and sweet.

Check our email warm-up guide if you need help with email warm-up.

The ideal length for a subject line is around 6-8 words or approximately 30-60 characters. This way, it's easily scannable and ensures the whole subject line is visible on both desktop and mobile devices. Long, wordy subject lines may not display in their entirety, causing your prospect to skip over your email.

Avoiding jargon or complex terms when composing your cold email subject line is crucial. Simpler language is easier to understand and increases the chances of your cold email being opened.

Don't assume your prospect knows every technical term or industry acronym you use daily. They might be familiar with some terms, but using common, easily understood language that resonates with most people is always safer. This increases the odds that your email will pique their interest, encouraging them to read further.

Remember, your goal is to communicate your message effectively, so simplicity should always be a priority. Ensure your cold email subject line is easily understandable and reflects the content of your email.

Free of Clickbait

Clickbait might improve open rates temporarily, but it can damage your reputation in the long run. People will quickly feel misled if the content of the email doesn't match the subject line.

This will make them less likely to trust you and your brand, eventually hurting future sales outreach efforts.

Trust is crucial in any relationship with potential customers or business partners. Therefore, it's important to establish and maintain trust by avoiding misleading tactics like clickbait.

Also, using clickbait can backfire by causing your email to be marked as spam.

Many email clients and filters are smarter now and are designed to identify and block misleading content.

So, instead of reaching your prospects, your emails might end up in the junk or spam folder. This will significantly reduce your email's effectiveness and decrease your overall ROI (return on investment) for that campaign.

Types of Subject Lines

Personalized Subject Lines

Personalization is crucial in cold emailing, where you typically reach out to someone who may not be expecting an email from you. In these cases, standing out from the crowd becomes essential.

It helps capture the prospect’s attention and demonstrates your interest in their work or company. Doing so makes your email more likely to be read, and the likelihood of receiving a response is significantly increased.

Also, using personalized subject lines increases engagement with your emails and reflects positively on your brand image. It sends a message to your prospects that your company is detail-oriented and values personal connections.

Incorporating this strategy into your cold email campaigns can significantly build your brand's reputation and credibility.

Here are some examples of personalized subject lines:
{Prospect name}, {pain point}
{Prospect name}, thanks from {your business name}
{Prospect name}, Do you know about {product or service}?
{Prospect’s name}, do you want to increase revenue?
I made a custom report for you, {prospect name}
Have a look {prospect name}
Exclusive offer for {prospect industry} leaders like {prospect name}

Asking Questions

Using a question as your subject line engages your reader in a way that a simple statement might not. People are naturally curious, and posing an interesting or thought-provoking question can make them more keen to discover your email's insights or information.

It's not just about any question, though. It's essential to pose a relevant question about the prospect’s industry, company, or interests.

The question should help readers see the value in your email and make them eager to learn more about how your services or products can benefit them. To craft an effective question-based subject line, balance piquing curiosity and providing context. You want the question to be intriguing enough that the recipient can't help but open your email, but not so vague that they have no idea what to expect inside.

Additionally, avoiding overly complicated language and sticking to simpler, more conversational phrasing will make your subject line more appealing and easier to digest. Another helpful tip when utilizing a question in your subject line is to keep it open-ended rather than something that can be answered with a simple yes or no.

This encourages further exploration and discussion by the recipient, ultimately leading to a more meaningful conversation and better results for your cold email efforts.

Here are some examples of asking questions in subject lines:
{Prospect name}, want to level up?
Looking to boost {specific task} ROI?
Curious {prospect name}? Let's connect.
How are you solving {pain point}?
How does {competitor} do it?

Mutual Connections

Mutual connections refer to individuals or entities that both the sender and prospect know and trust. By referencing a shared acquaintance in your subject line, you're quickly establishing a sense of familiarity, rapport, and credibility with the recipient.

Using mutual connections within the subject line is helpful because it leverages the psychology behind our natural affinity for familiarity.

People are more inclined to engage with others who share common interests, experiences, or relationships.

Remember that the objective of a mutual connection subject line is not to boast or name-drop for the sake of making an impression; rather, it should genuinely demonstrate the connection between you and the recipient. Be transparent and convincing in your choice of words.

Here are some examples of using mutual connections in subject lines:
{Mutual connection} recommended I contact you
We met at {event}
Really enjoyed your post on {common social group}
Referral from {mutual connection}
{Mutual connection} wants us to meet?
{Mutual connection} told me to reach out

Short Subject Line

Short subject lines aim for a word count of 6-8 words and focus on being concise, relevant, and intriguing. Their brevity makes them easily digestible and helps to generate curiosity among recipients. Additionally, they work well on mobile devices, where display space is often limited.

Why are short subject lines so powerful in cold emails?

For one, they cut through the noise and help recipients quickly understand the email's content. With so many emails vying for attention, these concise messages stand out, giving potential readers a reason to open the email and learn more.

Also, short subject lines exude confidence and say that the sender recognizes the prospects' time and attention are valuable. The success of short subject lines depends on striking a balance. Too short, and it risks sounding incomplete or vague. But if it's too long, it loses its punch and may not fully display on certain devices. The magic lies in finding that sweet spot that communicates the intended message clearly, engagingly, and concisely.

Here are some examples of short subject lines:
Request to connect
Moving ahead?
My mistake!
Your Priorities
Let’s discuss {prospect’s pain point}
Improve your email deliverability with

Follow-Up Email Subject Line

The importance of a well-constructed follow-up email subject line when reaching out to prospects cannot be overstated.

Effectively communicate your intention as a follow-up, balancing persistence and respect, reassuring the prospect that you genuinely care about engaging with them and that the conversation is worth continuing. To achieve this outcome, consider the language you use in your subject line. Avoid overly complex or robotic phrases and instead opt for straightforward, easily understood language.

The subject line should showcase your follow-up email's thoughtful and personalized nature, making the recipient more inclined to open and read through your message. Avoiding being overly pushy or spammy is crucial. Maintain a sense of professionalism and prioritize clarity above all else.

Remember that your goal is to pique the prospect’s interest and invite further communication, not to create confusion or frustration.

Here are some examples of follow-up subject lines:
Thanks for your time, {{Recipient_Name}}!
Let me know if I am too persistent.
Let’s make a plan
Still thinking it over? This might be of help
You left your things at our place
It’s been a long time since we spoke.
Hey, have you forgotten?
Hello! Just checking in to see how things are going!
It’s time for a touch base
It’s time for us to chat again?
Our next moves.

Open-Ended Subject Line

When you send a cold email, you only have a brief window to capture a prospect’s interest; an open-ended subject line can do just that.

Open-ended subject lines are like a teaser that leaves prospets wanting more. Their main idea is to pique the prospect’s curiosity, making them wonder what's in the email, ultimately motivating them to click and open it.

So, what makes open-ended subject lines different from other types of subject lines?

They can capture the reader’s interest while leaving some essential information a mystery. One of the reasons open-ended subject lines work well in cold emails is that they create a sense of urgency.

Not revealing every detail upfront makes the recipient feel compelled to open the email for fear of missing out on something important. This can lead to higher open and click-through rates, ultimately assisting you in having more conversation with prospects.

Here are some examples of open-ended subject lines:
What’s next for {company name}?
Tech question for {prospect name}
Do you make these mistakes?
Did you know {company name} was doing this?
Do you face this challenge?

Pain Point Subject Line

At its core, a pain point subject lines address a specific issue or challenge your prospects may be experiencing. By pinpointing this problem and ensuring it is relevant to your target audience, you can create a sense of urgency or curiosity that encourages the recipient to open the email.

After all, if the subject line touches on a problem they are currently grappling with, they will be more inclined to explore potential solutions – which, hopefully, your email offers. Keep in mind that they are not about exploiting a person's vulnerability. Rather, it aims to demonstrate understanding and empathy towards your potential recipient’s situation.

To make it as effective as possible, ensure it is clear and to-the-point while maintaining a conversational, human touch. Remember, your email subject line is the first impression your prospects get – if it sounds robotic or overly sales-driven, chances are it won't draw them to open the email.

Here are some examples of pain point subject lines:
{Prospect name}, are you tired of {pain point}?
{Prospect name}, will you let me ask you a question about…?
A 5-step plan for your heated week
Stop wasting money on {product or service}
Save space with {product or service}
{Prospect name}, solve your {issue} with {product or service}

Tools to Test Subject Lines

Refine by Moosend

refine by moosend
Refine by Moosend offers a tool that uses artificial intelligence to analyze cold email subject lines.

It compares them to industry benchmarks, predicts performance, and provides tips for improvement, aiming to boost open rates.

Email Subject Line Tester by CoSchedule

CoSchedule email subject line tester evaluates the effectiveness of your cold email subject lines.

Using a scoring system out of 100, the platform assesses various aspects of your subject line to provide insights into its potential impact. Among the metrics analyzed are character count and the inclusion of emojis.

Additionally, the tool considers how the subject line will appear on both desktop and mobile devices, recognizing the importance of optimizing content for different viewing experiences.

Email Subject Line Grader by Net Atlantic

The email subject line tester evaluates the effectiveness of your cold email subject lines. It employs an analysis that considers various factors, including character count, emotional tone, and the power of words used in the subject line.

It aims to measure the impact and uniqueness of your subject line, providing insights into whether it might be perceived as too generic.

Based on this analysis, the tool offers suggestions on improving your subject line to make it more compelling and engaging.


What is a Cold Email Subject Line?

A cold email subject line is the brief and compelling phrase that serves as the first point of contact in an unsolicited email outreach.

That phrase makes them want to see what's got to say inside the email. You'll always find cold email subject lines popping up in sales, marketing, and networking messages. The goal is to make sure your target audience or prospect opens the email by making the subject line interesting, valuable, and relevant to them.

When creating your cold email subject line, you want it to feel personalized and connected to what your recipient cares about. This way, they're more likely to open the email and read what you have to say. To make your cold email subject line work really well, it's all about using the right words.

Keep it simple and focus on what matters most to the person you're reaching out to. That'll help you get their attention and make a positive connection.

Why is an Email Subject Line Important?

An email subject line is important because it serves as the critical gateway to engaging the recipient and enticing them to open the email.

It acts as the first impression, providing a concise preview of the content and influencing the recipient's decision on whether to read the message.

So, while it might seem like a small detail, it plays a huge role in getting someone to open your email and read your message.

Consider the subject line as a sneak peek into what your email contains. It's interesting and well-crafted; the recipient is more likely to click on it and read further. On the other hand, if it's weak or too generic, it might go unnoticed or even end up in the spam folder. Remember, nobody likes clutter in their inbox.


Wrapping up, crafting an exceptional subject line for cold emails isn't a one-size-fits-all process. To achieve success, you need to mix research, creativity, and a touch of personalization. By taking the time to know your prospects, trying various tactics, and closely assessing your outcomes, it's possible to excel in this often-overlooked aspect of email marketing.

Keep these points in mind: keep the subject line short and to-the-point, use impactful words to capture interest, and add a personalized touch whenever possible.

Above all, don't forget the significant impact a well-thought-out subject line has on piquing curiosity and sparking a conversation.

Looking for Spring Sales Subject Lines for eCommerce? Check out our blog!
Related articles
Improve your email deliverability now.
email deliverability