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E-mail Marketing for Professionals: Improve Opening Rates through Optimised Subject Lines

06.12.2016, 3m

Any good e-mail marketing agency will tell you that one wrong word and the opportunity is already lost. The subject line of an e-mail determines if it will be opened, or if it’s destined for the spam folder. With the right approach, the relevant keywords, and a hint of personal flare, the humble e-mail can become a powerful tool in marketing. Get your expert e-mail tips below. 

Better Subject Lines = Higher Opening Rates 

The number of daily e-mails sent will rise to 206.6 billion by 2017. Although a decline in private e-mail correspondence is expected, due to the frequent use of social networks, the number of business e-mails is expected to continue to grow. 

When it comes to e-mail marketing, effective subject lines are therefore becoming more and more important. People’s attention is already strained by their completely flooded inboxes. What does it say — what’s inside? Think about this carefully when crafting a new e-mail. 

Describe the Contents of the E-mail in the Subject Line 

Recent studies show that users prefer to open mail content that’s clearly described in the subject line. After all, the potential reader can only guess whether the content is of any interest at all to them. If the subject line is vague, the opening rate drops. We all get far too many e-mails to open each one and read in detail.

 "This is one of the most important points. You should not be too adventurous, do not risk disappointment," says Katharina Lieske, e-mail marketing manager at Trusted Shops. 

Stick to a Maximum of 40 Characters 

The subject line is limited in most e-mail clients and web e-mail interfaces. For mobile e-mail applications, the number of characters displayed might be even smaller than on the desktop. Market researchers recommend not squeezing more than 40 characters into the subject line. This finding coincides with the outcome of another study. Of 200 million e-mails examined, those with 28 to 39 characters for the subject line were the most successful. 

"The rule of thumb: the scarcer, the better," says Lieske. Trusted Tips: Create successful email campaigns - download our free whitepaper


Begin with the Most Important Word 

The primary keyword should be as far ahead as possible in the subject line. We call this front loading the keyword. This ensures the recipient will see it, even if their e-mail client cuts off part of the subject line. Again, the risk of mobile e-mail apps is higher than on desktop. 

"Formulate actively and not passively, for example: Save 20% with XY! And not: 20% discount on XY", reveals our e-mail expert. 

Do Not Name the Sender in the Subject Line 

Space in the subject line is precious and should be used sensibly. The sender information is displayed by modern e-mail clients, so save the space for more important information. Nevertheless, the sender is still important. 

"I only send e-mails with my personal addressand not something like", states Lieske. 

Don’t Use the Recipient’s Name in the Subject Line 

Even though a personal salutation seems like a pretty good idea, it should be avoided. The average user knows that the e-mail wasn’t specially written for them. Not only will you risk annoying them by being condescending, you will also waste space. 

Should You Forego Using Special Characters? 

Hearts, stars, and other symbols can look nice, but they sometimes seem daunting to the user. Also, not all e-mail clients can display such characters correctly. If you must use them, you should place them at the end of the subject line. 

"Test the use of special characters — there are successes with special characters, which depends on the target group and the context. Special characters can be a benefit to recognition," explains Lieske. 


The results of various studies on making the perfect subject line are relatively clear: describe the content of the e-mail. Don’t try to be too creative. If you do not treat the subject line as an advertisement for the content of the e-mail, it will damage the opening rate success. This honesty right at the beginning of the e-mail promotes trust in the subscriber. And trust is one of the most important elements of ecommerce.

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