7 Tips for Email Subject Lines that Actually Get Opened

The average inbox is cluttered with a near-constant stream of email. According to the Radicati Group, 182.9 billion emails are sent and received across the world every day — that’s about 65 emails per internet-connected person per day. To put it simply, there is a lot of competition for the attention of your recipients.

In this battle for attention, your subject line is your primary weapon. Subject lines are the gateway to your email. They often make the difference between an email being opened and it being ignored. In fact, 35% of recipients admit to opening emails based on the subject line alone.

Subject lines have a complicated set of responsibilities. They have to set expectations for the email, draw attention, and present value, all within a strict character limit. Perfecting your subject lines and effectively fulfilling these responsibilities is a difficult, but rewarding pursuit. Here are our seven tips for email subject lines that drive opens.


The typical email inbox displays 60 characters of a subject line (often less on mobile). These 60 characters are your first impression, so they have to stand on their own. Accordingly, subject lines should be under 60 characters (preferably under 50). Statistically, subject lines of 28–39 characters performed the best.


An email should have a single, specific focus. The subject line should reflect this focus with specific keywords, placed as near to the beginning as possible. Assuming they’re audience-relevant, these keywords can simultaneously capture attention and set expectations. They also help your email to get picked up in inbox searches and sorting folders.


Why are you emailing? Did they sign up for a newsletter, complete a product trial, or submit a support ticket? Your subject line has to correspond to the actions and expectations of the recipients.

For example, if the user has subscribed to a newsletter, they’ve demonstrated interest in your content and a desire to receive more. They haven’t indicated anything about purchasing. They don’t want or expect a hard-selling subject line. In this case, it would be best to use a simple, straightforward subject line that identifies the newsletter.


The best subject lines elicit an emotional response from readers — they peak curiosity, make them laugh, or make them think. These subject lines incorporate an element of company personality and culture. Disruptive subject lines come in a variety of forms.

Intentionally vague subject lines can be mysterious and entice readers to find out more. Similarly, provocative subject lines can draw opens from surprise or curiosity. Witty subject lines can get a chuckle (or a groan), but are usually reciprocated with an open.


Questions are effective for many of the same reasons as disruptive subject lines. Questions don’t come off as pushy as an announcement or command. They create a more conversational, personalized feel.

Questions that are closely aligned with buyer needs and interests will draw attention and opens. Ideally, you should mimic questions recipients have already asked themselves. Obviously, questions posed in the subject line should be answered by the content.


In an inbox, message after message creates a daunting block text. Subject lines tend to be similar in length and general appearance, making the text block that much more amorphous. When catching up on emails, users tend to skim the subject lines rather than fully read through each. Numbers, punctuation, and symbols break your subject line up and help you get noticed by scanning readers.

That being said, it’s important to not to overuse these characters. Overuse of numbers, punctuation, and symbols makes your email appear spammy. An instance or two of any of the three will serve the desired purpose, without going overboard.


Personalization in email subject lines is a bit of a polarizing issue. Some sources wholeheartedly recommend personalization, while others will argue that it’s ineffective or even detrimental. Interestingly, personalized email subject lines usually show up among both the best and worst performing.

In our experience, personalization has been an effective tool with a couple of caveats. One mistake companies make is never personalizing beyond the recipient’s first name. This practice has become much more commonplace, limiting its effectiveness.

More effective personalization incorporates elements like company name, location data, and interest targeting. The other key point in personalization is not to overemphasize the personalized information. Don’t make a name or city the first word in your subject line, don’t highlight the information with stars, and certainly don’t write it in all capital letters.




HIPB2B is a demand gen solution provider, utilizing content, email, and marketing automation to drive outcomes for marketing and technology clients

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HIPB2B is a demand gen solution provider, utilizing content, email, and marketing automation to drive outcomes for marketing and technology clients

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