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Want Better Open Rates? This Is How Long Should Your Email Subject Line Be

Crafting the perfect email takes quite a bit of investment. The copy, the images, the call-to-actions and even the formatting all have to be just right in order to get the best results once the email has been opened.


But what happens if everything is just right inside the email and no one bothers to open it up?? Nothing. Nothing happens. Your amazing content is completely missed and so are your campaign goals.


Industry reports say that up to 47% of recipients open email based solely on the subject line. Additionally, 69% of recipients report email as spam based on the subject line.


You can see the importance subject lines have on the success of your open rate. The sole job of the subject line is to sell the open. Regardless of who you are trying to connect with, be it an executive, a prospect, or even just a friend, the strength of your subject line will determine the odds of your email getting opened.


Being that mobile devices generally display fewer characters of the subject line than the desktop view, the question is: should your subject lines be shorter to accommodate your mobile favoring subscribers?


Marketo recently completed a survey over a six-month period in which they generated a sample of roughly 200 email campaigns with more than two million emails sent. Most of the subject lines were between 4 – 10 words long. Below is the resulting data for average open rates in relation to average click to open rates.



As you can see, the highest open rates happened for subject lengths of four words whereas the lowest open rates were for nine-word subject lines. However, the click-to-open rates didn’t correlate with the high open rates. As a result, it became necessary to take into account overall engagement, not just open rates.


To do this, they used the following metrics: open rates, opens, click-to-open and clicks.



The seven-word subject line came out on top for overall engagement. Add just one more word to make an eight-word subject line and there is a dramatic downturn in performance slashing it down to nearly half that of seven words. Amazing how little can tip the scales against your favor. Hopefully, this case study gave you some insight into how to evaluate your own subject lines for open rates, click-to-open rates, and overall engagement. Another thing to keep in mind when creating your subject lines, the recommended average character count for email subject line that converts is less than 50 characters. So, test your subject lines with 7 words and 50 characters or less. Now that we took a quick look at the impact that subject line count can have on open and engagement rates, let’s discuss the five types of subject lines that can help you sell that open. If you’re looking to improve your open, click and conversion rates, you’ll want to keep these subject line types in mind.

Subject Line Type: Curiosity Curiosity is a powerful element to use in your subject lines. It gives the recipient a driving reason to open the email. They won’t be able to help themselves BUT find out what it is you’re talking about. Once they’ve opened the email, keep the curiosity up in the body to improve your click through rate as well. Be sure to deliver something of value in the body, you don’t want to lose people to frustration.

Subject Line Type: Urgency or Scarcity People hate to miss out on things. The FOMO is real. A subject line that creates a sense of urgency can increase open rates by up to 22%. Put a deadline on the actions you’d like your reader to take. Use the same sense of urgency in the body as well as you move the reader to your CTA.

Subject Line Type: Free Offers Everyone likes free stuff. Give your subscribers a reason to be happy to be receiving your emails and give them a good reason to open and click what you send.

Subject Line Type: Announcements and Events Let your subscribers know what is happening in your company with announcements or invites to events and put the key information in the subject line. If you’re offering free or discounted tickets, you’ll probably want to lead with that.

Subject Line Type: Authority and Expertise If you know it, show it. If you’ve made an accomplishment, let your readers know about it. Do this by showcasing your achievements and expertise in your industry and crafting that into your subject line.

There is no other form of communication as effective as email to connect with your subscribers and convert prospects. Creating the perfect subject line with the optimal length for open rates and engagement can go a long way to helping you meet your marketing goals.

If you'd like to get some feedback on your email strategy, feel free to book a free strategy consultation. We'll give you advice you can use, no strings attached.