The Best Email Subject Lines

Optimize Subject Line

How to Write Good Email Subject Lines

Writing great subject lines is an essential task in email marketing. It’s the first – and, if you’re unlucky, the only – text that your recipients will read. Good subject lines make people want to read what you have to say. This leads to more opens, more clicks, and ultimately more success.

The challenge: You have to say a lot with very few words. It’s easy to forget that the recipient, unlike the author, still has no connection to the content. Your subject line is his or her only glimpse. You’ve got one shot. Your subjects have to create in your recipients a burning desire to open the newsletter. In this article, we’ll share some email subject line best practices.

What is a good subject line?

Checklist: Optimizing the newsletter subject line
The most important content first
Note length and character count
Newsletter includes what the subject promises
Discounts and coupons with concrete numbers
Note spam rules
Personal offers
Limited time offers

The main points of the newsletter subject line are the length, the content and the positioning of the content. All email subject lines are short. But the shortest subject lines aren’t always the best. Even more important is that whoever reads the subject line knows exactly what the email contains. The magic word is relevance: One should make the subject clearly relevant to the point of the mailing as early as possible.

Although a creative and appealing subject is generally a good idea, you’re better off saving the creativity for the actual email. In newsletter subjects you should instead describe what’s at stake in the email as clearly as possible. It’s safe to assume that newsletters tend to be opened when the subject -content connection is really clear.

You should also think long-term. Don’t trick your recipients into opening the email. If the email adheres to what the subject promises, you have a better chance of the next newsletter being opened. This doesn’t mean that the subject has to be boring. It’s just that the subject’s expectations need to be met in the newsletter. The subject could reveal for example, “Exclusive offers” or “Secret Tips”, which will be discussed in greater detail within the email.

One way you can optimize the subject line and make it more attractive is by advertising discounts or coupons. This should be tied directly to concrete numbers. If the reader can immediately identify a benefit for themselves, the subject has already done its job. However, it must also be careful not to become the target of spam filters. Writing in capital letters or using too many special characters tend to trigger spam filters and should be avoided. Read this comprehensive blog post about spam filters and blacklists to make sure your email won’t ever land in spam.

In order to create yet more incentives for opening the newsletter, you can try limiting the time period of your offers. An example might be subject: “€20 Voucher until Wednesday” or something more personal, “€20 discount voucher, valid only until Wednesday”. If you’d like it to be a really eye-catching email subject line, check out your contact’s purchase history and insert an item your subscriber has already bought.

Since making statements about the actual reactions of the target group is difficult on the basis of assumptions and presumptions, it’s worth it to test several variants by A/B testing. This allows you to test different versions against each subject and then optimize the subject line. The option with the best opening rate should then be sent to all recipients. Read more about multivariate A/B testing.

How long should the newsletter subject be?

The best subject length repeatedly leads to discussions. How long should the subject be, in order not to be cut off in various email clients and on different devices? Technical developments such as Smart Watches and tablets cause the newsletter length to be increasingly shortened. Again and again we read that the subject should therefore be as short as possible.

However, the highest read rates are not reached by the most extreme reductions. In fact, a recent study by Return Path found that the opening rate is the highest in a subject between 61 and 70 characters (ReturnPath, 2015). How can these claims be reconciled? The short answer: by first presenting the subject’s most relevant info. An online shop’s offer for 10% off all women’s shoes could be communicated in many different ways, depending on which statements are most relevant to the reader:

10% off women’s shoes until Sunday

Only until Sunday – 10% Off Women’s Shoes

Women’s shoes reduced – 10% off until Sunday

All three subject lines have the same content in principle. However, they remain very different statements. One should therefore think carefully about what content is most important.

Subject lines examples

Here are some email subject lines examples for any occasion:

The Welcome Email

Welcome to Newsletter2Go!

The Holiday Discount Email

Ha-ha-halloween Costumes 20% Off

The Last Call Email

Black Friday sale closes in 3 hours

The Flash Sale Email

Cyber Monday Flash Sale: All Shoes 50% Off

The How To Email

How To Write The Best Email Subject Line

The List Email

The top 5 ways to increase open rates by 170%

The Case Study Email

Write eye catching email subject lines [Case Study]

The Do This Email

Do [THIS] if you want write the best email subject lines

The What If Email

What if you knew all the email subject line best practices

The Avoid Email

Avoid these 10 newsletter subject line mistakes

The Can’t Believe Email

Can’t believe how easy it is to increase open rates

The Call Out Email

Hello marketers! Here’s how to increase open rates

The Results Email

How we increased open rates by 220%!

The Truth Email

The truth about writing the best email subject lines

The You Email

Could you be a top marketer in 3 months?

The New Post Email

New Post: How to Write The Best Email Subject Line

The Hack Email

9 hacks to write the best email subject lines

Overview: Maximum length of the subject

Various Email Clients like Gmail or Yahoo, and mail program like Outlook or Thunderbird, have a maximum character length for the subject. A current overview of the maximum length of the subject line can be found here:

Maximum number of characters
Gmail70 Characters
Outlook73 Characters
Thunderbird66 Characters
iPhone41 Characters vertically 64 Characters horizontally
Apple Watch16 Characters
Android27-30 Characters vertically 46-62 Characters horizontally
Tip: The word “newsletter” in the subject is a waste of space in most cases.

Design possibilities in your email subject line

Overall, there’s less freedom in the subject line than in the content of newsletters. You can’t use HTML formatting for images – it’s text only. This doesn’t mean that you can’t do anything with the subject, though. There are still some design options with which you can optimize the subject line. First, you can insert a variety of Unicode symbols in the subject line. If chosen to match the subject and content of the e-mail, they can be quite effective.

Secondly, personalized placeholders can easily be incorporated into the newsletter subject line. Then the recipient can be purposefully and personally addressed. When using personalizations, you should make sure to use them only in combination with personal content. This could be personally relevant event-related mailings or newsletters and personalized service. Otherwise personalizations can quickly backfire. Most recipients now know that with just as little effort, personal speeches can be inserted into the newsletter subject line. Customers will quickly notice if you’ve tried using too many personalizations as a way to sell off an impersonal advertising mailing as individual. In such cases, one is better off staying away from personalizations.
Here you can learn more about creating personalized newsletters and here about email newsletter design.

What is the significance of the pre-header?

The pre-header is a line of text that appears in some email clients and web mailers in order to complement the subject. There you can accommodate brief summaries or additional information found in the subject which may not have fit in the text. If no pre-header is offered, some programs will automatically deduct certain texts from the email body. Here, the pre-header can be very handy, especially if you couldn’t accommodate all of the important information at the beginning of the subject. Sometimes pre-header will be shortened if necessary, but you still have the possibility of using the combination of both text fields to enter more content.

Overview: Maximum length of pre-headers

Maximum Number of Characters
Gmail97 Characters
Outlook255 Characters
iPhone81 Characters vertically 137 Characters horizontally
iPad87 Characters

The following table also shows which clients and programs newsletter pre-headers are displayed at all.

Overview: Where is the pre-header displayed?

ClientsPre-Header displayed?

Email Subject Lines for Mobile Devices

More than half of all emails in 2015 were opened and read on mobile devices. The biggest limitation for the newsletter subject line on mobile devices: There’s even less space available. The subject lines are cut very short, depending on the device. With smartphones and particularly in Smart Watches, it is important to consider the combination of the first characters in the subject with the first characters of pre-headers. Anyone considering this checklist should see higher open rates in no time. Looking for more ways to optimize your emails? A premium teplate with responsive design ensures optimal presentation of your newsletter on any device. We’ll even send you a template in your own design. Learn more about the advantages of our newsletter software.

About the Author

Stefania Goldman
Communications Manager

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