Want to optimize email response rates?

Take a look at your subject lines.
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Last week, I discussed three modern spins on the elevator pitch. One of these stressed the importance of email subject lines. This is a huge topic in business communication, so I felt it warranted another post.

For some businesses, particularly those in sales or marketing, open rates of emails are very important, as they can indicate the effectiveness of a marketing campaign or sales promotion. Beyond that, subject lines can work to generate leads as well--the greater the amount of emails opened by prospects, the greater the chance for conversions into customers. Regardless of industry, however, no one wants their emails to be ignored. Email etiquette can be confusing--everyone seems to have an opinion on what is and isn’t acceptable in the world of online communication. Luckily, there are some basic tips that can be applied regardless of your profession.

Whether you’re sending out a newsletter, a promotion on a product you’re selling, or a personal message, there are a some surefire ways to make sure your emails are opened.

Here are a few do’s and don’ts to help you get the most out of your subject lines:


  • Keep it short: while a 2015 study found no correlation between subject line length and open rate, one thing to consider when composing a message is that 53% of all emails are opened on mobile devices. To ensure the subject line isn’t cut off, stick to keeping it to about 6-8 words or 40-50 characters.
  • Be clear: since subject lines are an indicator of what lies in the body of the email, it’s a good idea to be transparent. Although it might be tempting to write something clever or funny, if it doesn’t explain why the email should be opened, it’s best to stick to a straightforward title that relates to the content inside.
  • Use punctuation (carefully): while it’s best to be wary of using too many exclamation points, question marks are an effective way to engage the recipient. A question can also pique their interest, which may lead them to open the email to find the answer. Furthermore, from a visual standpoint, question marks can make a subject line stick out in a crowded inbox.
  • Make your emails personal: tailoring subject lines based on the recipient is important. Business or sales emails send a message about your company and your brand, which will influence how consumers perceive your business. Unlike some advertising platforms that display a pop up or banner for a matter of seconds, emails have the opportunity to stick around in your inbox. This is a great opportunity for brand awareness and visibility, which can be a helpful tool especially for small businesses.


  • Be overly promotional: it’s commonplace in inboxes to find hundreds of promotional emails--businesses of all sizes send out coupons, sales notifications, and other special offers. While it’s okay to stress deadlines, for example of an upcoming event or an offer that’s about to expire, there is a fine line between a sense of urgency and an email feeling overly salesy. According to this study, subject lines using the keywords “clearance” and “2 for 1” were much less likely to be opened, as they come across as too promotional.
  • Include URLs: while it’s a good idea to have a link to your site in the text of the email, putting it in the subject line often reads as spam. Furthermore, a URL doesn’t provide enough information about the email’s content, so there is no incentive for the recipient to open the message.
  • Use all caps or lots of exclamation points: although it’s often difficult to convey tone via email, ALL CAPS is widely seen as aggressive, and often feels like the sender is yelling at the recipient. If used sparingly, capital letters and exclamation points can express enthusiasm; using too many, however, reads as overwhelming.
  • Use clickbait: according to the 2015 study mentioned above, subject lines with keywords such as “shocking,” “you won’t believe,” and “secrets” were not likely to be opened. Although playing off a recipient’s curiosity often works in certain settings, such as on social media, when used in subject lines they actually hindered open rates, as these emails were assumed to be dishonest or spammy.

As long as email remains a major form of communication, subject lines will continue to hold importance, as they’re the first thing seen in a crowded inbox. While there is no magic formula for creating the perfect subject line, if you aim to keep it clear and short and stray away from being aggressively promotional, you’ll be on the right track to better response rates.

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