160+ Cold Email Subject Lines That Will Stand Out In Your Prospect’s Inbox

Do you know the odds of making your cold email stand out in your prospect’s inbox? Brace yourselves for some shocking truths to find the answer!!

306 billion emails were sent and received each day in 2020! And this figure is projected to grow to 333 billion by 2022!

That’s mental!

But thankfully, not all of them are business emails. According to the Radicati, there are about 125 billion business emails sent and received in 2018. That means an office employee receives an average of 121 emails in a day. That’s still a lot of emails!

Clearly, your prospect’s inbox is going to be cluttered. With so many emails, your prospects are most likely going to just scroll down their inbox to spot the ones that look important.

And with the competition getting tougher, the odds are only stacked up against you.

What do you do now? How do you make sure that the little missive you send stands out from the hundreds of other emails?

Subject line. Crafting sublime subject lines is the first step to write the perfect cold email

Subject lines have, inarguably, become the deciding factor when it comes to whether your emails are going to be read or not.

There is even proof to back that up. Convince&Convert has found that 35% of the email recipients open emails based on the subject line alone.
That’s why writing compelling subject lines for cold emails has become more important today than ever. These subject lines help your email stand out, set expectations about the contents of your email and what you have to offer.

So, here are the different techniques that can help you write effective cold email subject lines throughout your email campaigns.

8 Cold Email Subject Lines Techniques with Examples

Personalized Subject Lines

Personalized subject lines are 22.2% more likely to be opened, according to a report by Invesp.

Why does personalization work?

This is simply because the human brain is ingrained to respond/shift focus almost immediately when you hear or see something that is related to you. That’s instinctive human behavior.

And that is why you have to write subject lines that indicate, ‘yes, this is for you and about you..’ to your prospects. Personalized subject lines will easily catch the prospect’s attention in a crowded inbox. It will also give your prospects a hint about the pains you’ve taken to do the research.

💡 Bonus info: After researching and testing thousands of cold emails, we have put together a collection of email subject line templates proven to get more opens from your prospects. Download the free e-book.

But how do you personalize cold email subject lines?

Mentioning the prospect’s name or company or designation are old school techniques. Yes…they are fine but they’ve become very common.

Then, how else do you personalize subject lines?

More research.

Personalize around your prospects geography – mention conferences, events, ideas, workshops, etc; happening in their local area.

Personalize around their recent activity – comments on a blog, twitter posts, etc.

LinkedIn is the best place to learn about them, about their recent activity, articles they liked or commented, find out if there are any mutual connections(we’ll discuss this later in this post), etc. You can also check their Facebook or Twitter page to see what their personal interests, hobbies are. Armed with this information, you can connect with the prospects with a personalized email.

Subject Lines asking Questions

Judge a man by his questions rather than by his answers.

– Voltaire

In general, questions invoke an urge to search for answers. Do you know why?

For our nerdy readers, here is the scientific explanation…

Questions stimulate the new brain(or neocortex), which is responsible for higher-order brain functions such as sensory perception, generation of motor commands, spatial reasoning and conscious thoughts in human and language.

Simply put, when a human is posed with a question, the human brain develops a deep-seated urge to know the answer or to at least look for an answer. That is the reason why asking the right questions will invoke curiosity or will get the prospect to introspect 

However, how do you know which questions are the right ones to ask?

Questions in the subject line which are about their goals or the issues that they might be facing – pain points – are the most effective ones. Prospects are bound to be curious about what doubts you have about their goals, and how you can help them, hence making them open your email.

It’s not only important that you ask the right questions, it’s also important that you ask these questions at the right time. Reaching out at the right time and asking the right questions can get them to immediately respond to your email.


Now, how do you go about finding what relevant questions to ask?


Glance over their official website, skim through their latest articles and related news articles so that you get a general idea about your prospect company’s current mindset and understand their visions and goals.

Spotting pain points can be tricky. Look for specific indicators that can help you understand what they’re struggling with. Going through any recent forum questions, Quora posts, LinkedIn comments can give you an idea of what problems the company might be facing at that moment.

Come up with questions based on the pain points, topics, or goals and I can assure you that you will reel in prospects to your cold email.


Related: You can find additional information on the best personalized cold email subject lines at Cold Email Templates. This is the ultimate guidebook that comprises best-performing email templates and subject lines, tried and tested by industry experts.

Subject Lines with a Mutual Connection

We mentioned earlier about looking for mutual connections while researching about your prospect.

Why does mentioning a mutual connection work?

It’s pretty straightforward!

Because, if a mutual connection exists between you and your prospect, you are no longer a stranger to them.

The reason why you need to establish a common ground/mutual connection is so that your prospect can be put at ease; they will be quick to trust you and it will be easier to break the ice than when compared to being a total stranger.

But, what mutual connections should I be looking for?

This mutual connection can be anything; like a mutual friend, or being part of the same LinkedIn group, or even personal things like sharing the same hobby, supporting the same sports team, attended the same middle school, attended the same event/conference and so on. If you dig deep enough there will be a thing or two that can help you relate with your prospect – just don’t go stalker-level.

Moreover and most importantly, mentioning the mutual connection in the subject line can help grab the prospect’s attention to your email in their shambolic inbox. In a way, this is a more refined type of personalization. Something familiar – something they know is bound to catch their eye.

And, where do I find these mutual connections?

LinkedIn is again the best place to look for mutual connections. Look for common friends, see whether there is a topic you both like, or influencer you both follow. For personal connections, you can scour their Facebook and Twitter profiles and see if there is anything you relate to and use.

Short Cold Email Subject Lines

Our life is frittered away by detail…Simply, simplify.

– Henry David Thoreau

Short cold email subject lines work great. They just about convey what the email is about and stand out in a littered inbox. And short subject lines perfectly fit handheld device screens.

Over 55% of working professionals read their emails on their mobile. And an average mobile screen can only fit 4-7 words max. Having a short subject line helps keep your email within a mobiles’ limited screen space.

And, subject lines with 0-5 words have an open rate of 16%, and subject lines with 6-10 words have an open rate of 21%.

The definition of short can be subjective for each and every sales rep. So, whatever fits your needs, you can draft a small subject line for your cold email that conveys the crux of what the email is about.

Note: Sometimes it’s a good idea not to include any subject line at all. Sending an email without a subject line can make it stand out. Because your prospect is certainly going to notice an empty space in his/her inbox. However, don’t do this often.

Subject Lines that create Urgency

Subject lines that create a sense of urgency and exclusivity can give you a 22% higher open rate; according to a report by Invesp.

Why is creating a sense of urgency effective in getting a response from your prospect?

FOMO. Simple as that. The fear of missing out on something that may not be available in the future can make people act impulsively and make rash decisions.  Using certain keywords and phrases can make what you have to offer to seem scarce, rare and special.

However, instilling a sense of urgency is an age-old technique deployed by the marketing department over countless years. Having subject lines like, ‘Don’t Miss Out!’, ‘Summer Sale is ON!!’, or ‘Awesome Deals!’ are all marketing ploys to attract customers.

Apart from these standard ones, there are subject lines that can revolve and be specifically aimed at each prospect. Using the right triggers that pertain to each prospect can induce urgency.

How does a one go about creating this urgency in their cold email subject lines?

Find out if there are any events or situations that can bring about a sense of urgency and make the prospect want your product – a trigger event.

These events can be anything;

  • It can be an upcoming event,
  • A new regulation or law that’s going to come into effect,
  • A time-sensitive pain point,
  • The end of the quarter or year.

Using these events, you can create a deadline for your prospect. Drafting your subject lines around such events to generate the urgency will get them frantic about this event and make them look towards you for a solution; hence, opening your email. If you’re successful, it can immediately get things started off without all the pleasantries and small talk.

Subject Lines with Value Proposition

Consumers do not buy your products. They buy product benefits.

– David Ogilvy

Writing cold email subject lines with benefits that your product/service can offer or with solutions you can provide to remove the pain points will get the attention of the prospects. These subject lines are best effective when you get the timing right.

Now, how do you implement benefits in your subject lines?

Listing down and bucketing your prospects according to how they will use your product and how they can benefit from it should give you a clear picture. Then you can go about creating a value prop subject line that suits each and every prospect accordingly.

Coming up with subject lines for cold email that indicate what value/benefit you can offer is the key to baiting a prospect in. Anything related to their field of work, anything related to a solution that can solve their problems included in your subject line can get them to notice your email and eventually open it.


Related: You can find additional information on the best personalized cold email subject lines at Klenty Cold Email Templates. This is the ultimate guidebook that comprises best-performing email templates and subject lines, tried and tested by industry experts.

Humorous Cold Email Subject Lines

A good laugh overcomes more difficulties and dissipates more dark clouds than any other one thing.

– Laura Ingalls Wilder

Have you ever wondered why humor is encouraged in workplaces today?

Laughter relieves stress and boredom, boosts engagement and well-being, and spurs not only creativity and collaboration but also analytic precision and productivity.

That’s not me. That’s Harvard Business Review. They have an article saying how humor in the workplace environment is beneficial and all.

And I agree!

Prospects are people, after all, and will appreciate a joke or two from time to time. It takes them away from the busy day they are going through. And using a funny subject line not only puts your prospect at ease, it can really make your email stand out from all the other monotonous and bland content present in their inbox.

How do you get the right sense of humor?

Getting the right joke is tricky stuff and not everyone shares the same sense of humor as you. So, the jokes you tell your friends or family most certainly cannot be used here without proper refinement.

Learn a bit about your prospect – see what he/she likes or. For example, if your prospect is British or likes Brit humor, you can be innovative with some strong sarcasm and self-deprecating type of jokes – or you could just quote any fancy line from Monty Python! Who doesn’t love them?!

However, remember! Humor is subjective, especially in this day and age. So, make sure you know your audience and choose your jokes carefully. If done right and you get a laugh out of your prospect, you’d have earned major brownie points. If not, you might have to start drafting an apology letter.

Subject Lines with Social Proof 

When you say it, it’s marketing, when they say it, it’s social proof.

                                                                                                                   – Andy Crestodina

Did you know that 63% of consumers want to hear company claims 3 to 5 times before they actually believe them? 

Obviously, you cannot keep talking about your own company so many times. This is where social proofs come in handy. Social proof is a psychological phenomenon where people think that the action of others is the correct behavior for a given situation. 

Social proof in your cold email subject line is a great way to boost your email open rates.

Use the credibility and good name your brand has earned over the years to make a prospect open your email. 

Embedding social proof in subject lines is very easy but is often overlooked by most of the sales teams.  

Some of the common social proofs that you can add to your subject line include – 

  1. Testimonial
  2. Recent awards
  3. Influencer/celebrity mention
  4. Partnership with major brands

When you add such proofs to your cold email subject line, your recipient will start picturing you differently and in a  more positive way.


Writing cold email subject lines that are exceptional and attractive is not an easy task. Because different subject lines work for different prospects.

The best way to find the most effective cold email subject lines is to perform A/B testing for the subject lines. Write different subject lines while you test, but make sure that your that the subject lines are honest, designed to help you engage with your prospects, provide clear information and value about what you have to offer. 


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