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B2B Email Subject Line Strategies: Boost Your Sale’s Teams Replies Today

Your prospects inbox is crowded. Emails often get overlooked. You need to stand out with a B2B email subject lines that convert. Here's how to do it.
PUBLISHED:
February 8, 2018
Last updated:
September 1, 2024
Ryan O'Hara

Key Takeaways

The best cold email subject lines should pique curiosity and use personalization to get the prospect to open the email.

But email open rates don't really matter — the best B2B sales teams measure cold email response rates when measuring the success of cold email subject lines.

Make sure you're also matching the content in the email to the subject line while focusing on the needs of the prospects and not just what your business does!

Table of Contents

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You could write the greatest cold email in the world — but it won’t matter if the subject line sucks and no one ever reads it.

We’ve hosted a ton of “RateMyPitch” live cold email breakdown sessions that help sales reps write better cold emails. We’ve even launched our AI outbound message generator, Scribe, which can help teams come up with killer email subject lines that are more likely to lead to opens and, more importantly, replies and conversations.

Throughout our journey to help sales teams improve their prospecting efforts, one of the most popular questions people always ask us is:

“What subject line should I use for my cold emails?"

Let’s break down what constitutes a good cold email subject line in B2B sales and strategies your teams can start using today.

Your prospect's inbox is probably a mess

5 tips for writing good cold email subject lines

  1. The best email subject lines should be vague enough to pique interest
  2. The best email subject lines should set the expectation of what's inside
  3. The best email subject lines should be personalized
  4. The best email subject lines should not be selfish
  5. The best email subject lines should describe an email you’d want to receive

Before we get into the details of the tips above, we’d like to provide some quick commentary on how we evaluate b2b cold email subject lines and why many BDRs, SDRs, and even the most senior account reps might be doing it wrong. 

Former LeadIQ Chief Evangelist Ryan O’Hara notes:

“When I did prospecting at Dyn, I always tried to hold on to subjects that worked to produce opportunities. Doing this allowed me to become a better prospector since we didn’t have tools like SalesLoft or Outreach back then tracking open rates, replies, etc.”

Luigi Prestinenzi, Co-Founder & Head of Growth at Sales IQ Group, says the cold email subject line have to be clear, has be to short and to the point, and he usually recommends only using 3-4 words.

"Personalization is key: keep it short, keep it sharp. Make it about the problem you are helping them solve and don't make it about you."

The goal of your cold email is to get a positive reply, not just an open. Anyone can get a high open rate, but if you are trying to get a positive response that starts building a relationship, the real thing to track when measuring b2b cold email subject lines is replies.

Using this as a foundation, some of the biggest opportunities we’ve seen reps get made it easy to get replies from big names, not just small startups. Okay - now let's get into the best B2B cold email subject line strategies and why they work.

1. Good subject lines should be vague

We see so many people shoot off their company’s best bullet in the subject of the email. Where then is the incentive to open it and ultimately reply?

Let’s use an email from one of our own Business Development Reps to show as an example of why a vague email subject line can increase reply rates.

Jim (our BDR) found a prospect that was wearing a Hawaiian shirt and lei in their LinkedIn photo that was a good match with our ICP (Ideal Customer Profile). He decided to use that angle to start a conversation with the prospect. This is a way to use personalization without needing any fancy tools (or...even worse, using their alma mater!).

Screenshot of an email personalized to prospect's profile photo on LinkedIn (email content in caption)
Email content reads Subject: King of the Luau | Body: Hey Tim, Rocking the leis on LinkedIn man, awesome. Hope you were holding a Mai Tai too. Got a quick question actually - wondering what your team is doing for prospecting at the moment. I was thinking we might be able to help you find contact info for some new prospects. We've got a nice, smooth workflow with stuff like Salesforce and Outreach, so if you're using those even better. What do you think about chatting sometime?

A vague subject line is a great way to use curiosity to draw someone in to open and read your email. In many ways, an email subject should be like a personalized version of clickbait. 

Don’t be annoying clickbait, but think of the curiosity clickbait uses to draw interest on social media. How often have we all clicked on an article that had a vague headline off Twitter or Facebook. They got you didn't they!?

2. They should set the expectation of what's inside

Remember how we just compared a good email subject to clickbait? Clickbait sucks. You want to mimic clickbait, not act like it. 

The reason it sucks is that, more often than not, the headline is deceptive, and you’re ultimately disappointed after you read the entire article.

You never want to do this to a prospect. 

The best part of Jim’s email subject that we showcased isn’t just that it’s vague; it's that the body of the email matches the expectation.

Jim brilliantly didn’t sell out and just pitch LeadIQ either. He meets the prospect's expectation by bringing up the LinkedIn picture, which featured things we all would see at a Luau. 

How angry do people get when they expect something to be a certain way and that something disappoints? That same experience applies to email subjects. Jim isn't perfect - so one way he could have improved this cold email subject line is being a bit more clear such as " Is the King of the Luau King of Prospecting?"

3. Good subject lines should be personalized

The biggest advantage a human being has over automated marketing or sales emails is that when we are prospecting, we can personalize to anything at that moment. 

Too many prospectors fall into the trap of trying to find one subject line that can apply to thousands of people. Just because you see a high response rate to a subject line with certain prospects doesn't mean you can just copy and paste to everyone!

When trying to figure out what to make your cold email about, find some angles that focus on the human you are prospecting to first. If you can’t find an angle, you can use the company as a backup. 

If you’re looking for a great example of using personalization in a cold email subject line, look no further than one of our own customers, Wilson Lee from Boomtrain. After some research, Wilson would routinely personalize the subject of an email with the name of a band the prospect likes. 

The results spoke for themself - he more often than not got a phone call that started the relationship.

The point of writing cold emails is to connect with people and start a conversation. As sales teams, we must stop looking at marketing emails as textbook examples of what to send. Marketing emails have their own separate email structure and best practices to follow. 

A good marketing email ≠ a good cold email. 

4. Good subject lines should not be selfish

The best cold email subject lines are unselfish (same for the email body copy). What do we mean by this? Sorry to disappoint, but your prospect doesn’t care about your company’s name, awards, or achievements. So why do we keep using them in prospecting emails? 

Using a company name, brand, or feature in a cold email subject just sets the expectation that the rest of the email will be about YOU. 

Guess what. You’re not the hero in your buyer’s journey, so don’t act like one in the subject of your outbound messaging. 

Emails that are about you or your company rely on luck instead of your prospect's personality and needs to start a conversation or relationship. 

5. Every cold email should be something you would open

Before you hit send, simply read the subject out loud. Ask yourself, “If this came up on my phone as a notification or as an unread email in my inbox, would I stop what I am doing to read it and reply?".

If the answer is no, you should rethink the subject line. 

To take things a step further, use a text-to-speech reader to have your computer read your subject line out loud. You might get a different perspective on it by hearing it read out loud. 

Need help crafting the best email subject lines for b2b sales?

While these cold email subject line strategies can get you and your team on the right track - you might need some additional help coming up with subject lines to test out.

Our AI message generator, Scribe, can pull insights from LinkedIn activities, Twitter, podcasts, company facts, news, job postings, and more to write subject lines and the body of your emails for you — or at least give you a strong starting point!

With all that said, cold email subject lines are important as they can truly make or break your cold outreach. Give them the attention ithey deserve!