How to Write the Perfect Email Subject: Complete Guide

An email marketing campaign consists of various elements that, together, will define the success or failure of the campaign. The email subject is one of the most important elements, and its effectiveness will largely determine a satisfactory outcome for the campaign.

By following some simple best practices, you can maximize the performance of the emails sent to your subscribers.

In this post, we will teach you everything you need to know to write a perfect subject for your emails, and increase your open rate.

What is an email subject? Definition

The subject of an email (subject, in English), is the line visible from the inbox by the subscriber, indicating what the content of the received email is about.

It is one of the three visible elements, along with the pre-header and the sender’s name, that a user will see without needing to open the email.

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The importance of writing a good subject for your emails

As we have said, the subject is one of the first elements visible to the subscriber, in an inbox presumably crowded with other emails.

Therefore, it is the element that will determine whether your subscriber opens the email or not, significantly impacting the open rate, one of the most important metrics in email marketing campaigns.

However, since Apple activated Mail Privacy Protection, some opens are recorded even if the subscriber hasn’t read the email. That’s why it’s also advisable to look at clicks and conversions to know if a subject is effective.

Without neglecting the rest of the email elements (template, content, links, CTAs, etc.), if you don’t have an effective subject, your email will remain unopened and the rest won’t matter much.

Best practices for subjects

Next, we will list a series of best practices for writing a good subject that increases the efficiency of your emails.

Summarize

One of the first keys is that, as we have said, the subject will serve for the reader to know what to expect from the email and, based on that, open it or not.

It is advisable, therefore, to carry out a synthesis exercise so that this phrase faithfully reflects the content of the email so that the reader feels interested in it.

What is the correct length?

The answer to this question is: it depends. Each email client displays a different number of maximum characters in its inbox, and even fewer are visible on mobile, so the important part should be at the beginning.

You must also consider the variety of devices on which subscribers check their email, with their respective screen size differences.

If the subject is too long, there is a high probability that it will be cut off at some point. On the other hand, if it is too short, you will hardly be able to condense the necessary information to arouse the reader’s curiosity.

Therefore, it is about reaching a middle ground where you can express the content of the email concisely and effectively.

Use keywords

Include important words related to the campaign theme and, if possible, as early as you can. This way, you ensure they are read on any device and situation, and predispose the reader to open the email to learn more about the topic.

On the contrary, try to avoid unnecessary words that do not contribute and take up space like “Hello” and other types of greetings that you can include in the body of the email.

This, in addition, will help those users who use filters or searches to find emails later.

Arouse curiosity

Although the subject serves for the subscriber to get an idea of what they will find inside the email, you must keep something to maintain that curiosity that encourages opening it. It’s not about deceiving (as we will see later), but about trying not to give too much away so that it’s not worth clicking on your email.

Use the appropriate tone

As with everything related to the content of your campaigns in general, it is very important that you know your subscribers and adapt the tone when addressing them.

Gather as much information as possible on this matter, and try to find a voice with which they feel identified and comfortable when receiving your emails.

Conduct A/B tests

Conducting a test between two subjects, sending them to a small part of the list and seeing which one works better, is a good practice that can significantly impact achieving a higher open rate.

Conducting this type of experiment is very simple, and here you have all the information about how to conduct A/B tests in your campaigns.

If you run out of ideas, an AI tool can give you dozens of subject variants in seconds. Choose the best ones and test them with an A/B test.

What NOT to do in email subjects

It is as important to know the best practices that can lead you to success as it is to avoid those that can hinder your campaign results.

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Avoid clickbait

Although we have talked about how the subject should generate enough curiosity for your subscribers to open the email, you must avoid falling into clickbait.

If you put a misleading subject, your email may be opened the first time, but if the content does not deliver what it promised, you will generate frustration and only achieve that the subscriber does not open subsequent campaigns or, worse yet, unsubscribes or marks your emails as spam.

Forbidden words

You must also keep in mind that there are certain words that trigger spam filters, as emails containing them are often related to unwanted or fraudulent content.

These are mainly terms related to money or financial entities, medications, prizes, sexual content, etc.

Types of subjects and examples for your campaigns

Below you can see some examples of campaigns and subjects that can increase your open rate.

Informative

The idea is that with a simple glance, the subscriber knows the relevant information about the content.

“New store opening near you”

Urgency generator

Generating urgency is a good way to increase opens.

“Only available for the next two days: download this ebook”

Personalized

Personalization always yields good results.

“Pablo, we have a series that might interest you”

Lists and numbers

Lists have been a very popular content in recent years for a reason: it’s hard not to read them.

“15 things you need to know to write a good email subject”

Questions

Another effective approach is to use question marks to engage the reader.

“Do you know how to get more clients thanks to email marketing?”

“How to”

How-tos also tend to attract curiosity very effectively.

“How to build your database efficiently”

Scarcity

Especially in the case of physical product sales, announcing scarcity is synonymous with success.

“Air Jordan Classic 82: last units”

Controversial

Although always with caution, a more controversial tone can work.

“Why your marketing strategy is wrong”

Imperative

An imperative tone (also always with caution and without overdoing it) can work well by directly engaging the subscriber to take action.

“Join our community”

Statistical

The use of statistics and percentages can yield good results, especially in educational and informative content.

“The main reason to use SMS Marketing: 98% open rate”

Sneak peek

A “sneak peek” at devices or other types of content that interest the reader will undoubtedly arouse their curiosity.

“Discover all the details of the new iPhone”

FOMO

It stands for Fear Of Missing Out, meaning the “fear of missing out.” Playing with this psychological factor also tends to work.

“Are you going to miss our webinar?”

Conclusions

The email subject is a very important element in defining the success or failure of your emails and campaigns.

Therefore, it is worth considering these best practices and taking the time to think it through, conduct the necessary tests, and measure the data to improve it in subsequent emails.

If you have questions about this or any other topic related to email marketing, contact us and we will help you.