Cold Email · · 9 min read

10 Cold Email Subject Lines That Get Replies

You only get one chance to make a good first impression, and a cold email subject line is exactly that. Get it right and email open rates will soar!

cold email subject lines

They say you only get to make a first impression once, and when it comes to cold email campaigns, it’s the subject line that makes the impression on you. It’s the first thing that the potential client or customer sees and is your opportunity to grab their attention. Falter and this stage and your carefully crafted email content are going straight to the trash without even having eyes set on it. But get it right and you’re looking at replies, opportunities, new clients, and profit.

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What's A Cold Email?

Let’s roll it back a second and start from the top. First of all, it’s important to understand exactly the type of email we’re talking about within this article. Cold emails are a very particular type of email campaign that serves a certain purpose. They’re emails that are sent to people who potentially have never heard of you but have certainly not had any contact with you before. They’re sent to receive a certain response. There are many responses that you might be looking to receive.

You might send a cold email with the aim of opening a conversation and literally just getting a response and beginning a dialogue. You might want a customer to complete a specific action, such as signing up for an ongoing newsletter or using a coupon code on your website. It could be that you want them to visit a particular page on your site such as an offer or content page. Whatever the aim is, cold emails work best when there is a required action you’d like the prospect to complete. Without one, without a purpose, people are unlikely to respond out of the goodness of their hearts.

The main issue with cold emails is that the majority of people don’t like to receive them. Having your inbox invaded by someone you don’t know (who is potentially trying to sell to you) just isn’t a pleasant experience. Does that mean you should, morally, write off cold emailing? No. The trick is to make it an email that is worth some of that person’s time. Start selling immediately and you’re no different to a billboard on the side of the road or an advertisement on the radio. Add personalization and the human element, showing that you’re an actual person on the other end of this email, that goes a long way to getting the desired effect underway.

Types Of Cold Emails

There’s no hard and fast definition for cold emails, each should be tailored to the situation, the audience, the campaign, and the actions that you’d like the prospects to take. That said, it’s possible to generalize to an extent and consider some of the wider categories that cold emails might fall into.

Complimentary Many campaigns pick this route because, frankly, who doesn’t like to receive a compliment, especially from a stranger (and not your mom). The nuance within a cold email of this type is to dig into the company you’re sending it to and find something specific that you like about the way they work, their past work, or the services they offer. This is more difficult on a vast scale due to the level of intricate personalization but it certainly works.

Addressing Pain Points If you’re offering your services to a prospect, the chances are that you’re offering a solution to their pain point. Clearly identifying their current issues, empathizing, and then offering your products or services as a solution is a great way to get prospects to already imagine a world where they’re pain-free and using your services.

Tell A Story That’s not suggesting that you sit down and write a saga into an email, but sharing stories where you’ve helped previous clients who match their current situation is a great way to introduce yourself. This could be legitimate social proof from a previous case study or it could be a work of fiction. Either way, telling stories is a great way to grab attention.

It’s important to note that these aren’t the only options available to you, but they cover a lot of options. Some senders prefer to build a relationship over a period of time, acting slowly and nurturing the prospect. Others go in hard and fast, likely working at volume, with the aim of getting as many eyes on their emails as possible and pushing for sales early. What works will depend on the type of business, products, or services that you’re offering and the audience you’re working with. Tailoring your campaign is key.

Why Do Cold Email Subject Lines Matter?

Putting it into simple terms, they matter because it's the first thing that your prospect sees and it allows them to make an immediate generalization about the type of company you’re representing. So yes, they do matter.

Now that we’re clear that subject lines are important, let’s dig a little deeper. Many skilled marketers have put effort into exploring the effects that different subject lines have on open rate and response rate. This is completed through a process known as A/B testing. You send a batch of emails with a certain subject line, you then send another batch with a different subject line. The content is the same, the inbox the same, the sender the same. The only thing that gets changed is the subject line. The results are compared and you can see different levels of success.

Marketing writer (and current Head of Growth at William Wickey did some extensive testing of various subject lines. He found that straightforward subject lines such as “Your sales process” received fairly mediocre open rates of 37%. A more personalized subject line that included the company name, “Potential leads for [company name]” was opened a far more appealing 61.1% of the time. However, when you add in hyper-personalization “I found you through [Contact-first-name] [Contact-last-name]” the open rate rocketed to a staggering 86.6%.

Yes, subject lines are largely successful when considered in the eye of the beholder, the human aspect. But it’s important to consider the computer side of the equation. The last thing you want is your campaign ending up in someone’s spam folder, and subject lines play a part in deliverability.

Attention must be paid to; subject line length, word use, and emoji use.

Subject lines that sit between 36-50 characters have the best open rates but only by an extra percentage point when compared to slightly longer ones.

Word use is incredibly important. Certain words and phrases such as “Free”, “% off” and “Satisfaction guaranteed” are among a long list that will activate many spam filters. Ditch the gimmicky and outdated sales speak and, instead, focus on the individual opening the mail.

Emojis in Subject Lines

emojis in cold email subject lines

Emojis are still a cause for debate in the email world. There are those who have and will never put an emoji in an email, let alone a subject line, and there are those who may as well write exclusively in emojis. Whatever your personal standpoint, it was found that contextually relative emoji use had a positive effect 60% of the time.

How To Write A Cold Email Subject Line

Writing a cold email subject line might have been treated as a simple throw-away item in the past, but now it should be treated as a work of art. It should be admired, nurtured, built on, and adapted over time. There are, however, some general rules that one should always subscribe to:

Avoid clickbait

Avoiding writing clickbait-y titles should be a rule for life, not just cold email subject lines. Telling readers that you’ll be able to “500x their revenue”, or “sell 1000% more products with this technique” is never going to get you a legitimate open, and it’s highly unlikely that you’d be able to keep those promises anyway.

Use the subject line to build trust, rather than make promises that you can’t keep.

Keep It Short And Sweet

Short, sweet, and readable in seconds. If the person is going to give you their time by opening the email, they want to know what it’s about before they bother opening it. If you’re able to stick to the 36-50 characters, you’re forced to be clear and concise anyway.

Personalize it

The best cold email campaigns are personalized. People want to feel that they’re interacting with another human, not a cold, unfeeling robot. One of the easiest ways to personalize an email is to pull contact data from a CRM by using a cold email marketing tool. This means that you can personalize at scale. Consider using their name, company, and even their interests if you know them.

Make It Enticing

If you’re writing to offer something, a product or service, then at least make it seem like something that the reader wants. Pique their interest so they want to find out more, leverage connections you already have, or share related stats and figures. Encourage but don’t fall into a clickbait trap!

Offer value

Let them know you have something that they’ll find useful and of genuine value. This could be a personalized report you’ve generated, a resource that could help them, or an offer of legitimate assistance. Use the subject line to either immediately share the value you can offer or suggest how you can bring value to them.

Imply Urgency

Time-limited offers are as old as time itself. Creating a sense of urgency within a campaign can persuade people to act quickly and decisively. You might lose some people who don’t have the immediate time to respond within your “urgent” time frame, but creating urgency can get your email prioritized if the user is working through their inbox methodically.


You could be forgiven for thinking that keywords are exclusively used in the world of SEO or PPC, but including keywords in your subject line is useful for your prospects. It creates an easy way for potential prospects to understand the content of your email but also helps them to find your email at a later date using the search function of their inbox.

Cold Email Subject Line Examples

"[Mutual connection] recommended I get in touch"

Leading with a connection that you have between the prospect and yourself creates a sense of relationship. The connection is essentially acting as a referrer, and if the prospect is close to them it’ll go a long way! Referrals are by far the easiest sales to close, so leverage them where possible.

"A [benefit] for [prospect's company]"

Get specific, what benefit can you offer to their company. It could be a saving, it could be a boost to sales, or it could be assistance in some way, shape, or form. Keep it concise and chances are you’ll hook their interest.

"So nice to meet you, [Prospect]!"

This might not sound like a typical cold email, but a prospect might have left you their email via a newsletter signup or at a convention or meeting. You haven’t had email contact with them yet, but this is a great way to signify that a connection is already there.

"[Situation] at [Company]"

If you’re a service company this is a great option. “Referral software at [Company]” or “HR processes at [Company]”, whatever you sell link it to the company the prospect works for to create a connection.

"Will cut to the chase"

This indicates they’re not about to read a lengthy email, they won’t have to wade through a barrage of sales talk or essays, and it sounds interesting, “What’s this person so keen to tell me?”

"If you're struggling with [common pain point], you're not alone"

If you’ve done your research on the prospect, you already know their pain points, and even if you haven’t you’ll be able to generalize pain points that the whole industry has. Letting the prospect know that they’re not the only one suffering can go a long way, it shows you’re empathetic and, importantly, that you might be able to offer a solution.

"Will I see you at [event]?"

If an event is coming up, you can usually see invitees in advance through social media or via the organizers. If you receive a reply, it’s helpful either way. If they’re not coming, then you don’t have to waste time prepping to talk to them but you also have an opportunity to open a dialogue, “That’s a shame, can we catch up at…” If they reply positively, then you have the chance to create a meeting.

"[Referral name] loves us & thought you might, too"

As said above, referrals are the easiest conversions, and if you’re able to legitimately say that their connection already loves your services, chances are they’ll believe that they will love them too. They’ll be interested and want to find out more.

“You’re invited”

Short, simple, and interesting. “I’m invited to what?” The key here is to answer the question very quickly when they open the email, otherwise, you’ll have a high open rate but a low response rate. You could use this literally, and enclose an invite to an event, or figuratively “You’re invited… to explore your [insert service] options”

“Time for coffee after [Mutual Meeting]?”

If you know that you’ll both be at an in-person meeting, throwing out an invite in the subject line cuts straight to the point and many people will be polite enough to respond either way to a personal invite. Be wary of sending this out to too many people…

Key Takeaways

Cold email subject lines aren’t something that you’ll necessarily get right immediately. Remember that A/B testing will go a long way to measure success, just be sure that you have the right email campaign tool in place to accurately track the analytics so you have data to back up your tests.

  • Try a variety of subject lines using the same email content
  • If in doubt, always personalize your subject line
  • Tailor each subject line to the campaign, audience, and purpose of the email

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