Subject line

The perfect subject line11 tips to prevent your newsletter from ending up in the trash

To be clear, the perfect subject line can exist, but it is more like wishful thinking. After all, a successful subject line depends on more than just good wording. Other influencing factors, such as the time of sending or the target group, also have a major impact on the opening rate. For example, if you’re running a promotion for red sneakers, but the recipient bought a pair just a few days ago, the best subject line won’t help. Also, you may catch the wrong target audience. An example of this is if you’re promoting baby clothes, but your potential customer only registered with you because he or she needed a gift. Again, unfortunately, no subject line, no matter how good, is of any use to you.

Nevertheless, the subject line is essential for a successful newsletter. With a regular newsletter mailing list, you will probably never achieve a 100 percent open rate. But the better the subject line is formulated and the more suitable it is for the target group, the higher the open rate will be.

The subject line is, so to speak, the digital shop window through which you look when strolling through town. If you find the shop window appealing and are basically interested in the products, you’ll be happy to take a look. If this is not the case, move on – and the same applies to the subject line. Especially with the abundance of newsletters, recipients usually only open those that seem interesting to them.

Also, realize that while a high open rate makes a good impression, it’s only a stage win. The real goal is for the recipient to take the action you want them to take.

To ensure that your target group matches your offer as closely as possible, our EMM e-mail marketing software supports you with numerous filter functions.

So that your subject line also opens the doors, we have summarized the 11 most important points for you.

1. What's it about?

Even if it sounds natural, the subject line must make it clear what it is all about. Unfortunately, this is often not the case. In many cases, the recipient does not recognize what the content is. Mailings should also not simply be numbered consecutively, such as “Information Mail X/2021” or “Offers November 2021“. This is a waste of potential, because one or the other recipient who would have been interested in your cover topic will not open your mailing at all.

Become concrete. A subject line like “Only today 20% on all jeans” is much more meaningful than “Only for a short time reduced offers!“. It may be that some recipients do not open because they do not need jeans, but those who open know exactly what awaits them. This increases the chance of conversion.

2. Arouse interest

The subject is the first impression the recipient gets from a mailing. To ensure that it is not also the last, interest must be aroused. Therefore, avoid formulations that are too general. Rather ask questions or state important facts, “Free cancellation up to 2 weeks before departure” or “Have you already thought of your travel pharmacy?“. Theses, assertions and hit lists can also arouse interest, such as “The 10 best gifts for men“. Questions and assertions can also be combined, of course, like “Vacation wanted? Our best last minute deals! 🏝️” or “Fancy an aperitif? Momos has the best one 🍸“. Optimal triggers are also concrete instructions for action, formulated as succinctly as possible, such as “Secure the last tickets now“.

You can also arouse interest by using strong words, for example:

Subjective: Success, Ideas, Tips, Facts, Secret, Reasons

Verbs: save, win, achieve, convince

Adjectives: free, new, easy, successful, guaranteed

And provide for variety! If a subject is repeated, it loses its effect. As everywhere in life, the dose is crucial and too much of a good thing is bad in the end.

3. Become personal

The fact that a newsletter contains a personal address in the text should now be a matter of course. But what about the subject? Also here a personal address is possible. The chances of success are quite promising. Because the own first name catches the receiver immediately in the eye. Also a simple personalization with “you” in the subject can already upgrade the subject line. Example: “Our gift for you, Jenny!

Impersonal designations such as “one”, on the other hand, should be avoided completely. Make sure that the name is spelled correctly.

4. Positively occupy

A positive language usually leads to a more positive result. This is also true for the subject. Avoid words like “no” and “not”. These provide already from the outset for a negative tendency. Choose enough of its positive and activating words. That creates a good tendency and this transfers itself in the best case to the readers. The chance that the receiver opens the newsletter rises thus with it. SSo instead of “So you don’t smell unpleasant” better “Liz, everyone loves your scent“.

5. Generate (temporal) pressure

Most people get angry when they miss a chance, e.g. a good offer. Therefore, it can make sense to create a certain pressure with the subject line and to get people to act. Freely after the slogan, who does not buy now, is to blame itself. So communicate a deadline, such as “Order only 24 hours free of shipping costs” or “Last chance: Early bird discount ends at midnight“. Limited offers or remaining quantities can also be advertised in this way, “Limited edition: only 555 pieces available“.

6. Meet expectations

Anyone who comes up with special offers must also deliver them. Many know surely the mattress business, with which durably the clearance sale with special discounts is applied. They consider these once, perhaps still another second time, until you notice that everything is only mesh. It behaves similarly also with newsletter, and/or the pertinent subject line. So anyone who advertises with “Only today…“, “Now free of charge…” or “Once-only offer…” must also comply with this. Otherwise, the trust is quickly gone and the recipient no longer opens a mailing.

The perfect subject: The spice lies in the brevity

7. The spice lies in the brevity

A subject line should not be as short as possible, because your recipients are reading lazy or have a limited receptivity, but because it is otherwise not displayed completely. The advice for the correct length varies slightly. As a rule, at least 40 characters are displayed and, depending on the device and application, also 60-75 characters. Therefore, we recommend that you use 45 to 55 characters (for most desktop users). However, you should not hang yourself on three more characters if this would result in the message being lost. Formulate your subject line in such a way that the most important keywords are as far in front as possible, so that they are not clipped by any e-mail client after all.

For the content you can save irrelevant additions like “Daily Newsletter:…“, these only take up space and do not convey any content. An important point for the length of your subject line are also the end devices that your recipients use. As an EMM user, you will find this information in the EMM statistics. If, for example, you have a large number of mobile users, it is advisable to use subject lines that are as short as possible.

8. Payday

Numbers offer clear information and convey a certain technical competence. In addition, numbers already stand out in the subject because they are regarded as symbols and are therefore more eye-catching and memorable. Therefore, always use the number and not the word for numbers. This also saves characters. Discounts in the subject line should be taken with caution, as some spam filters react to this. Examples of this are subjects such as “Now 15 percent discount on…” or “20 Euro save on…“. Numbers from statistics, checklists etc. work well and less susceptible to spam, examples are “5 reasons for…“, “12 tips for…” and “90 % of our customers…“. In addition to numbers, other striking punctuation marks can also be used. Use these sparingly, however, so that your mailing does not appear dubious or is declared as spam.

9. Just Smile

As the saying goes: “A picture says more than a thousand words”. You can also take advantage of this in your subject line. Emojis first arouse attention and with the small pictures emotions can be conveyed quickly and easily. However these should not be used arbitrarily, but have reference to the topic, e.g. “🍁 With the sheets also the prices fall 🍂”. Use a maximum of 2-3 emojis, otherwise it will quickly appear dubious. On some occasions or partly in certain branches you should do without it completely. Here smilies can be regarded as frivolous and inappropriate. If you are not sure whether emojis is well received by your target group, it is best to send several split mailings. In the case of symbols with a different cultural background, depending on the target group, you should also pay attention to a possibly different meaning so that there are no misunderstandings. And important: Test whether the symbol is displayed correctly on different clients, as some emojis are not suitable for use in the subject.

You can simply copy the emojis into your subject line. In our blog post “Emojis – More emotions for email marketing” you will also find all common smilies and symbols well sorted.

10. Use pre-header

The pre-header is a supplement to the subject line and is displayed in many e-mail clients. Especially apps for mobile devices support the display of the pre-header. Therefore, the pre-header and the subject line should never be the same. The pre-header serves as a supplement to the subject. Use this opportunity to provide your recipients with more information than can be accommodated in a 45 character subject.

Here are some examples of how the pre-header has been well used to add valuable content information to the subject.

11. Practicable?

As the saying goes: The worm should taste good to the fish and not to the angler. It’s the same with mailings. A subject line that you think is great doesn’t have to appeal to your target group. Therefore the motto is: test, test, test. With an A-/B-Test, for example, you can quickly determine what is more popular.

Example: One of our board members was convinced that emojis in the subject of B2B newsletters are counterproductive and lead to fewer openings. His argument was that he deletes all emails with emojis unread. So he regarded his behaviour as standard. We did the test several times – and each time the variants with an emoji performed better. One of the winning subjects was: “The 10 most important newsletter key figures 🚀 28 % Open rate – all recipients“.

Of course, in the B2B environment, the subject must not lose its seriousness.

We wish you lots of fun and success with your copywriting!


With E-Marketing Manager (EMM), AGNITAS offers intuitive marketing automation software for creative multi-channel campaigns via email, web push, SMS, fax and print. The award-winning software meets individual data protection requirements as an in-house or SaaS solution and flexibly adapts to customer needs. From open source to high-end, there is a suitable variant for every budget.

When Martin Aschoff founded the company in 1999, AGNITAS was a pioneer of email marketing in Germany. Today, AGNITAS is one of the most renowned and innovative providers of high-quality marketing automation software, which is used around the world for customer-oriented communication.


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