How to Write Better Subject Lines and Increase Your Email Open Rates

9 min read
Dec 11, 2020
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What’s the most important part of an email? At first, you might think that it’s obviously what you find inside after you open that email. The truth is, nothing is more important than your email’s subject line. It’s like the headline of an article. An article needs to have a good headline to entice readers to get into the story's details. Without a good headline, even the best stories might go unnoticed. We can apply the same principles to writing your email subject lines. 

Think about how you browse your emails. You delete many of them without even opening them. We're all guilty of this. You probably do it automatically, without paying too much attention to everything that floods into your inbox. It’s no wonder when you consider that roughly 306.4 billion emails were sent and received each day in 2020. The figure is expected to increase to over 361.6 billion daily emails by 2024.

With 35% of email recipients opening emails based on the subject line alone, you can’t afford to write poor subject lines. How do you hook your readers so that they don’t just trash your emails and start opening them instead?

What’s an email open rate?

You need quality subject lines to get better email open rates. Before you move further, you need to make sure you know what an email open rate is. An email open rate is the percentage of emails that were opened out of the total number of emails sent. Obviously, the higher the percentage, the better. 

Now, what’s a good email open rate? Well, it depends. Mailchimp scanned billions of emails sent out by their system and calculated the average unique open rates and a few other metrics.

They analyzed 46 different industries, and, it turns out, the average email open rate for all of the industries they analyzed is 21.33%. Government-related emails have the highest open rates at 28.77%. Emails related to hobbies come in second, with a 27.74% open rate. Emails about religion came in third, with a 27.62% open rate.

These numbers offer just a glimpse into email open rate statistics. If you want to compare apples to apples and get more industry-specific data, take a look at Mailchimp’s email marketing benchmarks.

Chances are your email open rate is below average for your industry. Your subject lines are probably the main culprits. While it might be challenging to become an award-winning copywriter overnight, there are ways for you to take your email subject lines up a notch. 

Be clear and direct

Remember when I said there are more than 300 billion emails sent and received each day? Just imagine how difficult it is to get your recipients’ attention. And when they finally take a look at your subject line, the last thing you want them to do is start thinking about what the heck your subject line is about. Once they do that, it’s already a lost cause. 

Don’t make your recipients wonder what your email is about. Give them a reason to open it. It can be something that benefits them, solves their problems, makes them laugh, or piques their curiosity. One example from Hubspot that I particularly like when it comes to clarifying your benefits goes, "Increase your open rates by 50% today.” Now, compare that to a dull line like, "How to increase open rates." See the difference?

Limit yourself

Don’t waffle. Don’t waste your space with unnecessary words. Keep in mind that a typical inbox will only show about 60 characters of your subject line. That’s, more or less, nine words. 

It’s even more important to be brief when you realize that people open 46% of all emails on their mobile devices. Open your email app, and take a look at the emails you receive. Those emails should give you an idea about how long of a subject line to shoot for. If your subject line rambles on with too many details, it will get cut off. 

While you’re at it, Mailchimp advises limiting punctuation as well. According to their research, you shouldn’t use more than three punctuation marks in your subject line. Otherwise, your emails will likely look like spam.

A/B test your subject lines

After a while, you might get a feeling for what resonates with your audience. No matter what email marketing tool you’re using, you’ll also find hard data related to your open rate and many other metrics. 

Based on your experience and previous campaigns' performance, it should be easier for you to write new subject lines. The best part is that you can A/B test your subject line ideas. What does that mean? You need to prepare two different versions of your subject line. Later, send the first version of your subject line to one group of your recipients and the second version to another group. Once you get your campaign results and find out the open rates for each of your subject lines, it should be easier to tell in which direction you should go in the future. 

You should know that you don’t have to split test your total number of recipients. Run your test on two small groups of users and determine the subject line that performed better. Then, send your emails with that specific subject line to the rest of your recipients. 

Ask a question

Your subject line doesn’t have to be an affirmative sentence. In fact, asking a question instead can increase engagement and improve your open rate as a consequence. 

What kind of question will work best? Take a look at the conversations your customer service agents have with your customers. Your customers start conversations with your agents because they have problems to solve. Asking about those problems in your subject line will encourage your recipients to open your emails. 

Make a list of questions that might serve as a potential subject line and choose the one (or two, if you want to test) that you’ll use. Oh, and make sure you actually answer your question in the main body of your email.

Don’t forget about the email preview 

Sometimes you’ll want to say so much in your subject line that your text just won’t fit. That’s when preview or preheader comes into play. Preview is that line of text that directly follows your subject line and is visible in an inbox without opening the email. 

Obviously, it’s a lot more difficult to draw your recipients’ attention to the preview, but it can be a nice complement to what you say in your subject line. Don’t let that opportunity go to waste. Also, keep in mind that if you don't set the preview text yourself, the email client will automatically pull the preview from the body of your email or display information like “Message clipped.”

Segment your list

If you have a vast email list, it’s more than likely that you won’t be able to please everyone with your emails. Try to avoid sending the same message to all of your recipients. They signed up for your newsletters for various reasons, so give them content tailored to their preferences. 

How you segment your email lists is unique and entirely up to you. I’m responsible for our monthly newsletter at LiveChat, and while we’re talking about a basic distinction, we divide our audience into two different segments. They correspond to different roles that our customers have assigned to their licenses. I send two versions of our newsletter. One goes to the managers, and the other one goes to customer support agents. 

Both groups have a lot in common, so the newsletters’ content is similar. However, some sections of the newsletter for the managers are tailored specifically to them. It’s the same with the newsletter for customer support agents. Some of the stuff that we share with managers is merely irrelevant to agents and vice versa.

Think about it the next time you draft your emails. Email marketing tools give you plenty of criteria to base your segmentation on. Take advantage of that. As Hubspot rightfully pointed out in their article, it would be a shame to send steakhouse recommendations to a vegetarian, wouldn’t it?


At some point, I bet this has happened to you. You meet someone for the first time, and then they forget what your name is and start calling to you in an awkwardly impersonal way. It feels the same way when you subscribe to an email list and then start receiving emails without your name mentioned anywhere. 

Nobody likes those impersonal emails. We all want to be recognized to some extent, and adding a personal touch to the emails you send to your recipients is a great way to build rapport with them. If, for some reason, you don’t want to use a recipient’s first name in your subject line, make sure to mention it in the email preview or when you greet a person in the opening line of your email. 

You get to know your recipients’ names, but there’s a lot more data you can collect about them to make your personalization even more granular. However, personalization is more about the main body of your email rather than the subject line itself. 

The next time you’re going to draft your subject lines, keep in mind that research has shown that emails that included the first name of the recipient in their subject line had higher click-through rates than emails that did not.

Throw a bit of persuasion into the mix

As with all things marketing, good subject lines involve a little bit of psychology. Persuasion techniques work most of the time, if not always. The ones that seem to work best with email subject lines are scarcity and urgency. Let your subscribers know that your offer is limited in quantity or time. People tend to value limited items more. Don’t overdo and sensationalize your subject lines, though. It’s easy to use words that trigger spam filters and send your emails where nobody will even look at them.

We all want our open rates to be as high as possible, and writing compelling subject lines is the best way to do that. No one knows your audience better than you do, and all the knowledge you have will make things a lot easier. It will take a lot of trial, error, and testing, but eventually, you’ll get there.

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