write better email subject lines

How to Write B2B Email Subject Lines that Convert

When it comes to B2B sales, there are many factors that contribute to a successful campaign. From lead generation to sales calls to email campaigns, each step is a chance for you to make a strong impression. As such, it’s worth spending the time to make sure that every part of the process is well thought out and executed properly. In this article, we explore why email subject lines are important, and how you can write the best B2B email subject lines possible. 

Why it’s important to spend time crafting a good subject line

Let’s start with the basics – why are B2B email subject lines so important? After all, it’s a very minor detail when it comes to the overall email marketing plan. However, in reality, it’s the kind of detail that can determine how ultimately successful your efforts are. 

The subject line of your emails will often be the first thing that people see. Don’t forget, you’re trying to stand out from a sea of other emails, and you only have a few moments to make a good impression. A hastily crafted subject line can mean that the recipient doesn’t even open your email. 

You’ll have no doubt spent a lot of time crafting the contents of your email. However, if you don’t put some thought into the subject line, that hard work could well go to waste. So, if you’ve been working hard to capture different types of B2B leads, you don’t want to throw it away at the last hurdle. 

Key elements of a quality subject line

According to email experts Mailchimp, there are several elements that make up a successful email subject line. They researched a whole host of metrics from their users to determine what was and wasn’t successful in this area. Here are some of the key areas they highlighted: 


By adding each recipient’s name or location through merge tags, you can make your emails eye-catching from the off. This type of content often works well across all types of users and is relatively easy to implement. 


The direct approach often works best here. You want your recipient to know why they should click to open your email rather than just send it to their trash. Avoid slogans where possible, and instead cut to the chase. 


When you’re sending B2B emails, the recipients are likely going to be short on time. Craft a short and simple email subject line that will get their attention. 


Avoid things like excessive punctuation and emojis. Doing so can easily make your email look like a spam message. 

Tips on writing a good subject line

Good Email Subject Lines

So, you’ve got some of the basics on what makes for the best B2B email subject lines, now let’s look at further details. When you’re writing your subject lines, you’ll want to spend some time coming up with ideas and creating something that’s going to connect. Here are some things you might want to try: 

  • Keep your audience in mind. You should already know who your key segments are and what they’re likely to respond to. Always keep this in mind when creating email content. 
  • Tell them what’s inside. Again, this links back to being descriptive. Tell your recipients what they’ll find within the email, and make it as appealing as possible. 
  • Pose a question. Asking an industry-relevant question can be an excellent way of grabbing attention, particularly if you can provide an answer within the email. 
  • Don’t mislead. You want to make sure that the email subject line reflects the contents of the email. Don’t make false promises or try and trick people into opening it.

What you should avoid when crafting your subject line

Now that we know some of the things you should do and what you might want to include, it’s time to mention some aspects you might want to avoid. Below, we’ve highlighted some of the email pitfalls that can mean you don’t manage to progress your leads any further through your B2B sales stages

  • Avoid spam filters. The last thing you want is to include a subject line that’s going to indicate spam. Avoid things like currency symbols, ‘100%’, ‘act now’ and anything spammy. 
  • Don’t add ‘RE:’. If your email isn’t a reply, you shouldn’t start the subject line with ‘re:’. It can be misleading and frustrating and may mean your email is reported as spam. 
  • Avoid spelling errors. Check and then double-check your subject lines for spelling and grammar errors. 
  • Don’t use only one word. Your subject line should be more than just a one-word greeting. See our tips above for more detail on length. 
  • Avoid exclamation marks. You don’t want to seem overly excited/cheesy with your subject lines, so keep excessive punctuation away from them. 

B2B email subject lines best practices

subject line best practices

Whether you’re creating a small email send list or you’re running an AI email marketing campaign, it’s worth seeing some examples of good content. We’ve picked out some best practice ideas to help get you started: 

  • FOMO (fear of missing out). Would you like to try [your service] for free? 
  • Short and sweet. Answers to your questions. 
  • Ask a question. Are you disappointed with your [lead pain point]? 
  • Personalize.Hi [name], we met at [industry event]. 
  • Use numbers. 10 tips to achieve your [lead’s_goal] in 2021.
  • Power words. Introducing our new [service] update for 2021. 

Of course, you can take elements of these and change them as you see fit. However, you’ll see that they all meet the criteria that we’ve outlined earlier in the post. 

Subject lines you should avoid using

bad subject line examples

If you’re still not sure what sorts of things you should avoid, we’ve picked out some bad examples of email subject lines. These break many of the rules that we’ve already established and can be off-putting to potential clients:

  • Avoid click-baiting. Congratulations! You’ve qualified for our amazing offer!! 
  • Don’t give away too much detail. Top email tip: avoid overly detailed subject lines that give away too much. 
  • Don’t look like spam. Looking to save cash?! 100% guaranteed ways to save! 
  • Don’t use all caps. YOU’RE INVITED! 

Although some of these are painful to read (and somewhat exaggerated), they’re the types of things that you should try and stay away from. You wouldn’t open them, and neither would your potential customers. 

Tracking and testing

The last thing to mention about writing the best B2B email subject lines is testing. You’re not going to perfect your process straight away. Your customers are unique to your business, and the types of things that work and don’t work will vary greatly. The only way you can know what’s right for your business is through tracking and testing. 

Make sure to pay attention to key metrics such as open and click-through rates. You can then use A/B or multivariant testing to further refine your craft. With these insights, you’ll have a better idea of what’s appealing to your customers and how you can reach them in future. 

Final thoughts 

Clearly, email subject lines are a lot trickier to create than at first glance. With a limited amount of space, you need to create something that’s going to encourage your readers to click through. However, anything that looks too try-hard or spammy isn’t going to work. 

By taking some time to craft something worthwhile and appealing, you have a much better chance of reaching those on your mailing list. You should also track and analyze your results to see what is and isn’t working.