Subject Line Tips to Increase Cold Email Open Rates

August 16, 2021

Email marketing remains one of the essential B2B sales tactics used on the Internet. And while many other forms of communication have come and gone — the art of the cold email is as relevant as ever. And while email marketing automation has made this sales channel easier to manage, you can’t achieve the conversions you want without good content. 

A 1% open rate is almost an industry standard — not a lot of cold emails get opened by prospective leads. The reason for that is apparent; people just aren’t hooked by most of the subject lines written out there. 

The subject line makes or breaks your email campaign. It’s the only thing that determines whether someone will open your email; after all, there’s no second chance at a first impression. And that’s why learning how to write a killer subject line is the only thing that matters for increasing cold email open rates.

Front-loaded Value

Do you know what a B2B sales email and the script for a YouTube vlog have in common? 

While these writing formats are different in almost every conceivable way, both need to deal with short attention spans. The window of opportunity for capturing someone’s attention online is smaller than ever — an unprecedented abundance of content, vendors, and products has made sure of that. 

Since the start of the smartphone era, the average consumer’s attention span has fallen — they’re far less patient with unengaging content. That means you need to demonstrate value or spark interest right away, at the beginning of your subject line. Otherwise, your recipients might not even read it in its entirety. 

Avoiding long subject lines is a good rule of thumb, but if you absolutely need a long one — make sure that the gist of your message is found in the first five words. People are mainly opening their emails on smartphones these days, and that might be all they see of your subject line on the smaller screens. 

Inciting Curiosity 

One of the best things about email marketing is that it’s easily deployable and available to everyone — but that’s also one of the worst things. Most companies use email marketing, which means that any member of a particular target audience receives countless emails all the time. 

This has made people wary of cold emails — and it has made enticing subject lines more critical than ever. While writing a subject line, you need to spark curiosity and interest, incentivizing the recipient to open the email, ultimately increasing response rates. 


People perceive most emails sent from business addresses as spam — which is why your email subject line needs to stand out from the rest. Personalization is a great way to do that because it makes the rest of the content seem more organic and heartfelt. Most recipients are more likely to open and respond to an email whose subject line contained their name.

This makes the rest of the offer look more custom-tailored, something everyone appreciates. And personalization goes both ways. Recipients want to hear from other people, not faceless companies and big brands. That’s why sending your email from an alias or a personal email address will increase open rates as well. 

Engaging Recipients Right Away

Above all else, the subject line needs to be one thing — interesting. Customers need a reason to engage with your subject line and open the rest of the email. That’s why you should consider including:

  • A piece of news related to their industry
  • A statistic relevant to their work
  • A CTA about their industry

It’s essential to make the subject line all about the prospect rather than your offer and company. Once they open the email and engage with your content, you’ll have plenty of opportunities to make a pitch down the line. However, don’t go for the conversion right in the subject line — the goal here is to nudge them towards opening the email. 

Being Informal When Appropriate

It’s important to remember that prospects are fully aware of how much email marketing has become automated in the past two decades. They know that they’re just one of the thousands of other leads receiving your email blast — and they hate it. 

That’s the main reason why personalization is so important even in the subject line; building trust with prospects is not easy, and they want to feel like they’re not just another number. And that’s also the reason why informal writing has become increasingly popular in email subject lines and body texts. 

Using humor in the subject line immediately makes your message jump out of the countless boring and impersonal corporate emails. Of course, writing something funny to any target audience is far from easy — but that’s precisely why it’s so effective. People don’t expect to get a chuckle out of a B2B sales email, and already getting them to laugh at the subject line is a big win. 

Ironically, the more mature and serious an industry is, the better its members respond to funny emails. Such people are tired of pretentious and formal communication, and your subject line will be a breath of fresh air — as long as it’s tasteful and objectively funny. And as long as you don’t overdo it and make the email look spammy, using an emoji can also make your email more eye-catching amidst a sea of generic ones.

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