Email subject – What is the email subject?

The email subject is a brief description of the content of the email that is presented to the recipient without the need to open it. This element is visible from the inbox, along with the sender’s name and the pre-header , that is, the first sentence of the email.  

Its main function is to give a preview of the content of the email; this serves to attract the recipient and convince them to open it. It is a great ally to hook customers since it is the first impression they receive.

The importance of the email subject


If the subject of the email is not attractive, you will never be able to differentiate yourself since your email will end up in the trash with many other emails that the user receives from other companies. If users have 60 unread emails, it will delete them all at once. To avoid this, the subject should be treated as if it were a title and its goal is to stand out from the rest.

On the other hand, when the email subject is differentiated, this will cause the email to be opened and this influences the opening rate . The opening rate is one of the most important metrics to take into account when sending mass emails as it defines the success or failure of the campaign. 

How to write a perfect email subject


To write an email subject that causes opens, several aspects must be taken into account:

The length

A short subject line can attract the customer more so they have a higher open rate apart from the fact that a long subject line may not read well on all devices.

The pre-header

It consists of the first sentence of the email and which usually follows the subject if we have not gone too far with its length. This must be taken into account since it can complement the information on the matter.

spam words

We must avoid words that take us directly to the spam folder. These are common words but are often used by spammers, such as “invoice”, “urgent”, “free”.

Avoid capital letters and special characters

Abuse of these can land you in the spam folder. Avoid writing everything in capital letters and using percentage signs (%), currencies ($, €) or excessive use of exclamations or quotation marks.

Generates expectations and mystery

It helps to tempt users and encourage them to open the email, thus increasing the open rate but keep in mind that you must create real expectations. A notable example is from Freepik: “The best is yet to come… In fact, it is inside this email”

Feeling of urgency

Subjects that give a feeling of urgency, that it is something that is going to end, cause greater openings since they invite people to open the email to avoid missing something really good. Some examples could be: “Last 24 hours for a wonderful discount” or “Today is the last day to…”

Warns of danger

If you want a person to do something and you tell them to do the opposite, it is very likely that that person will eventually do what you want. An example could be “Do not open this email if you want to have clients.”


Apart from adding the recipient’s name, you can also personalize the subject based on the user’s interests, preferences or location.

Ask questions

With this strategy you will awaken the curiosity of users who will want to open the email to get to the answer.

Examples of email subjects that cause opens

These are several examples of email subject lines with high open rates that will inspire you:


“Sound like a DJ at your next party”

It is a way to invite users to share Spotify, to feel powerful and to explore the different options that Spotify has.


“Wrong foundation? Never more”

Through a question, she answers one of women’s biggest problems: makeup base.


“Get the best sellers before they are sold out”

It produces a feeling of urgency in case the offers run out, in this way the user is tempted to open the email to see what these offers are.


“We are extending the promotion by 1 day! Get your place from 16.99 euros”

It is another case that produces a feeling of urgency since the promotion has run out but they have extended it so the user is also forced to open the email.


“20% discount on ALSA for you”

The subject is addressed especially to you, it makes the user feel unique and is a very useful way to attract the user to your brand. On the other hand, the amount of discount that the user can obtain is also another reason to open the message.